Just to clarify, the spell hit cap for every class without talents/hit rating is 202.
At lvl 70, you have a 17% chance to miss a lvl 73 mob (all raid bosses are lvl 73). Since you can't eliminate misses completely, you can go up to 99% hit. Remember that; 12.6 spell hit = 1% chance to hit.
Since you need 16% it's 12.6*16% = 201.6 (202 rounded up). Balance of power gives you 4% spell hit, which means you need 12% more to cap. 12.6*12%= 151.2 (151 rounded)