Should the seller be entitled to forfeit any amount paid on account of any purchase of the property, the seller shall pay to the broker 1/2 of such monies, subject to a maximum sum equivalent to the seller's commission.

我不理解的是最后一句的"maximum sum"有没有包括我另外给的2%.如果不包括的话,那我应该给.如果包括的话,那2%就是maximum了.