The fellow who created the original made the background to coincide with a modified CT_PlayerFrame.xml (from the CT_UnitFrames addon). The health/mana percentages were centered on the actual colored bars, and the currHP/maxHP and currMP/maxMP were in the area to the right of the bars. The original CT method was to have the xxxx/xxxx text over the bars with the percentage just to the right of the bars (with no background behind the %s).
Hopefully that makes sense to you and doesn't cause more confusion. :D