OK, this is how I worked it out with Excel formulae - assume the total hours are in A2, with column B for Basic hours, column C for OT15, and column D for OT2, then these formulae can be put in the cells stated:

B2: =8*INT($A2/12)+MIN(8,MOD($A2,12))

C2: =2*INT($A2/12)+MAX(MOD($A2,12)-8,0)

D2: =2*INT($A2/12)+MAX(MOD($A2,12)-10,0)

Put other totals in A3, A4 etc., then copy the formulae down.

Hope this helps.

Pete