I've got a similar power, maybe a step lower than yours. I managed to complete and compete in higher levels of orchestra band without actually learning how to read music. I would be able to play the song after hearing it a few times. I use sheet music as an instruction (if needed) on which notes to play (this note equals this fingering on the instrument) rather than speed/tempo of the song. Applies to whistling/singing too.

And very similarly the on the fly ad-libs which makes for some funny "jokes" I can throw around with friends as I'm not very good with actual jokes.