28-88 seems significant, but 55-115 just isn't comparable, even though they change by the same value, amirite?

Are you high?

Yes, 88-28 is 60, as is 115-55, but the percentage change is higher for the jump from 28 to 88. That's over triple, while 55 to 115 is barely more than doubling. That's why it seems more significant, because it is.