Yeah, comparisons are always going to be complicated.
About 65% of my commissions are for independent t-shirt design so licensing is just rolled in. I charge based on amount of visual elements and complexity but the standard range is $65 to $100 a design. I could conceivably charge more on one out of every four designs but that would only be based on those individuals own ability and hustle to move products featuring themselves.
And I've said it before on other posts... Independent Wrestlers (who are my largest client base) often bring a lot of mistrust and spotty business acumen to the deal.
Anyhow....love your paintings and you deserve every cent you charge and more.