You'll need to edit the inc_func_member.asp file and change the function which handles displaying the stars (make a backup of the file before you edit it). It looks like this currently
function getStar_Level(fM_LEVEL, fM_POSTS)
dim Star_Level
select case fM_LEVEL
case "1"
if (fM_POSTS < cLng(intRankLevel1)) then Star_Level = ""
if (fM_POSTS >= cLng(intRankLevel1)) and (fM_POSTS < cLng(intRankLevel2)) then Star_Level = getCurrentIcon(getStarColor(strRankColor1),"","")
if (fM_POSTS >= cLng(intRankLevel2)) and (fM_POSTS < cLng(intRankLevel3)) then Star_Level = getCurrentIcon(getStarColor(strRankColor2),"","") & getCurrentIcon(getStarColor(strRankColor2),"","")
if (fM_POSTS >= cLng(intRankLevel3)) and (fM_POSTS < cLng(intRankLevel4)) then Star_Level = getCurrentIcon(getStarColor(strRankColor3),"","") & getCurrentIcon(getStarColor(strRankColor3),"","") & getCurrentIcon(getStarColor(strRankColor3),"","")
if (fM_POSTS >= cLng(intRankLevel4)) and (fM_POSTS < cLng(intRankLevel5)) then Star_Level = getCurrentIcon(getStarColor(strRankColor4),"","") & getCurrentIcon(getStarColor(strRankColor4),"","") & getCurrentIcon(getStarColor(strRankColor4),"","") & getCurrentIcon(getStarColor(strRankColor4),"","")
if (fM_POSTS >= cLng(intRankLevel5)) then Star_Level = getCurrentIcon(getStarColor(strRankColor5),"","") & getCurrentIcon(getStarColor(strRankColor5),"","") & getCurrentIcon(getStarColor(strRankColor5),"","") & getCurrentIcon(getStarColor(strRankColor5),"","") & getCurrentIcon(getStarColor(strRankColor5),"","")
case "2"
if fM_POSTS < cLng(intRankLevel1) then Star_Level = ""
if (fM_POSTS >= cLng(intRankLevel1)) and (fM_POSTS < cLng(intRankLevel2)) then Star_Level = getCurrentIcon(getStarColor(strRankColorMod),"","")
if (fM_POSTS >= cLng(intRankLevel2)) and (fM_POSTS < cLng(intRankLevel3)) then Star_Level = getCurrentIcon(getStarColor(strRankColorMod),"","") & getCurrentIcon(getStarColor(strRankColorMod),"","")
if (fM_POSTS >= cLng(intRankLevel3)) and (fM_POSTS < cLng(intRankLevel4)) then Star_Level = getCurrentIcon(getStarColor(strRankColorMod),"","") & getCurrentIcon(getStarColor(strRankColorMod),"","") & getCurrentIcon(getStarColor(strRankColorMod),"","")
if (fM_POSTS >= cLng(intRankLevel4)) and (fM_POSTS < cLng(intRankLevel5)) then Star_Level = getCurrentIcon(getStarColor(strRankColorMod),"","") & getCurrentIcon(getStarColor(strRankColorMod),"","") & getCurrentIcon(getStarColor(strRankColorMod),"","") & getCurrentIcon(getStarColor(strRankColorMod),"","")
if (fM_POSTS >= cLng(intRankLevel5)) then Star_Level = getCurrentIcon(getStarColor(strRankColorMod),"","") & getCurrentIcon(getStarColor(strRankColorMod),"","") & getCurrentIcon(getStarColor(strRankColorMod),"","") & getCurrentIcon(getStarColor(strRankColorMod),"","") & getCurrentIcon(getStarColor(strRankColorMod),"","")
case "3"
if (fM_POSTS < cLng(intRankLevel1)) then Star_Level = ""
if (fM_POSTS >= cLng(intRankLevel1)) and (fM_POSTS < cLng(intRankLevel2)) then Star_Level = getCurrentIcon(getStarColor(strRankColorAdmin),"","")
if (fM_POSTS >= cLng(intRankLevel2)) and (fM_POSTS < cLng(intRankLevel3)) then Star_Level = getCurrentIcon(getStarColor(strRankColorAdmin),"","") & getCurrentIcon(getStarColor(strRankColorAdmin),"","")
if (fM_POSTS >= cLng(intRankLevel3)) and (fM_POSTS < cLng(intRankLevel4)) then Star_Level = getCurrentIcon(getStarColor(strRankColorAdmin),"","") & getCurrentIcon(getStarColor(strRankColorAdmin),"","") & getCurrentIcon(getStarColor(strRankColorAdmin),"","")
if (fM_POSTS >= cLng(intRankLevel4)) and (fM_POSTS < cLng(intRankLevel5)) then Star_Level = getCurrentIcon(getStarColor(strRankColorAdmin),"","") & getCurrentIcon(getStarColor(strRankColorAdmin),"","") & getCurrentIcon(getStarColor(strRankColorAdmin),"","") & getCurrentIcon(getStarColor(strRankColorAdmin),"","")
if (fM_POSTS >= cLng(intRankLevel5)) then Star_Level = getCurrentIcon(getStarColor(strRankColorAdmin),"","") & getCurrentIcon(getStarColor(strRankColorAdmin),"","") & getCurrentIcon(getStarColor(strRankColorAdmin),"","") & getCurrentIcon(getStarColor(strRankColorAdmin),"","") & getCurrentIcon(getStarColor(strRankColorAdmin),"","")
case else
Star_Level = "Error"
end select
getStar_Level = Star_Level
end function
The function starts around line 92
Change it so it looks like this (this basically removes the bit that displays the extra star each level but still changes the star graphic thats shown as a user goes up a rank)
function getStar_Level(fM_LEVEL, fM_POSTS)
dim Star_Level
select case fM_LEVEL
case "1"
if (fM_POSTS < cLng(intRankLevel1)) then Star_Level = ""
if (fM_POSTS >= cLng(intRankLevel1)) and (fM_POSTS < cLng(intRankLevel2)) then Star_Level = getCurrentIcon(getStarColor(strRankColor1),"","")
if (fM_POSTS >= cLng(intRankLevel2)) and (fM_POSTS < cLng(intRankLevel3)) then Star_Level = getCurrentIcon(getStarColor(strRankColor2),"","")
if (fM_POSTS >= cLng(intRankLevel3)) and (fM_POSTS < cLng(intRankLevel4)) then Star_Level = getCurrentIcon(getStarColor(strRankColor3),"","")
if (fM_POSTS >= cLng(intRankLevel4)) and (fM_POSTS < cLng(intRankLevel5)) then Star_Level = getCurrentIcon(getStarColor(strRankColor4),"","")
if (fM_POSTS >= cLng(intRankLevel5)) then Star_Level = getCurrentIcon(getStarColor(strRankColor5),"","")
case "2"
if fM_POSTS < cLng(intRankLevel1) then Star_Level = ""
if (fM_POSTS >= cLng(intRankLevel1)) and (fM_POSTS < cLng(intRankLevel2)) then Star_Level = getCurrentIcon(getStarColor(strRankColorMod),"","")
if (fM_POSTS >= cLng(intRankLevel2)) and (fM_POSTS < cLng(intRankLevel3)) then Star_Level = getCurrentIcon(getStarColor(strRankColorMod),"","")
if (fM_POSTS >= cLng(intRankLevel3)) and (fM_POSTS < cLng(intRankLevel4)) then Star_Level = getCurrentIcon(getStarColor(strRankColorMod),"","")
if (fM_POSTS >= cLng(intRankLevel4)) and (fM_POSTS < cLng(intRankLevel5)) then Star_Level = getCurrentIcon(getStarColor(strRankColorMod),"","")
if (fM_POSTS >= cLng(intRankLevel5)) then Star_Level = getCurrentIcon(getStarColor(strRankColorMod),"","")
case "3"
if (fM_POSTS < cLng(intRankLevel1)) then Star_Level = ""
if (fM_POSTS >= cLng(intRankLevel1)) and (fM_POSTS < cLng(intRankLevel2)) then Star_Level = getCurrentIcon(getStarColor(strRankColorAdmin),"","")
if (fM_POSTS >= cLng(intRankLevel2)) and (fM_POSTS < cLng(intRankLevel3)) then Star_Level = getCurrentIcon(getStarColor(strRankColorAdmin),"","")
if (fM_POSTS >= cLng(intRankLevel3)) and (fM_POSTS < cLng(intRankLevel4)) then Star_Level = getCurrentIcon(getStarColor(strRankColorAdmin),"","")
if (fM_POSTS >= cLng(intRankLevel4)) and (fM_POSTS < cLng(intRankLevel5)) then Star_Level = getCurrentIcon(getStarColor(strRankColorAdmin),"","")
if (fM_POSTS >= cLng(intRankLevel5)) then Star_Level = getCurrentIcon(getStarColor(strRankColorAdmin),"","")
case else
Star_Level = "Error"
end select
getStar_Level = Star_Level
end function