Morkaischosen, what douglas is saying is that the cap will never go above your original caster level. In particular,

First casting:
Maximum caster level = x + x/2, or 3x/2, where x is your original caster level.

Second casting:
Max. caster level = x + (first casting max)/2 = x + 3x/2/2 = x + 3x/4 = 7x/4

Third casting:
Max caster level = x + (second casting max)/2 = x+7x/4/2 = x + 7x/8 = 15x/8

This patern continues forever, so your maximum caster level is always modeled by the equation x + (((2^n) - 1)x)/2^n, where x is your original caster level and n is the number of repetitions. Since (2^n) - 1 will never match or exceed 2^n, your maximum possible caster level will always be less than double your original caster level.

Doesn't mean it isn't a neat trick though.