C rating is mainly used as a comparative discharge rating. Your Dads has 250amps and yours has 325amps. As the C rating has climbed higher and higher, there's isn't really much diff from a practical point. The higher C rating should have a lower IR and hold voltage better versus load than a lower C rating. Might be hard to measure diff between 50 and 65 C rated lipos.

There's a noticeable diff between a 20C and a 50C, but as you've found, diff in a 50C and 65C is hard to notice.


C rating is also used in charging specs btw, such as a 5C charge rated lipo, for a 5000mah that would mean it could be charged at 25amps