Formulae or Lookup Tables?

I've attached a sample spreadsheet. This sample only has Black, Caucasian and Hispanic races, and there is no differentiation between the pediatric and adolescent equations (but there are with other equation sets I'll be using). I've listed the equations I'll be using for this group; note that the parentheses may not be correct (I just pasted them in).

I just realized there's a problem with my lookup table; the age for adult males begins at age 20 while the age for adult females begins at age 18 . Any suggestions for this?

Thank you.