Espy, you may have sweetspotted the ledge with Spring simply because you either Sprang one frame before or the same frame on Sonic would've automatically snapped to the ledge.
I managed to pause it at the right time to get a picture of it. Notice how Sonic appears to be in two different sets of animation on at the same time?
Though as a researcher, I know better than to simply write off something like that so easily.
If/when Jerry gets home from Uni, I'm going to ask him if he can look into it himself. I want to get things done, but at the same time I'm only one person and I can't get everything done in such a short amount of time.