That would be handy. Maybe it's a commercial scheme to get people who don't know the exact number to buy more credits than they need to trans or whatever.

No, because you allready have to buy more credits than you need to trans something. It doesn't take 300 credits to trans, but you can't really just buy 289

For curiosity sake, these are lesson totals for Imperian. I know there are slight differences if you want to compare.

Inept to novice spend 7 total of 7
Novice to apprentice spend 9 total of 16
Apprentice to capable spend 18 total of 34
Capable to adept spend 56 total of 90
Adept to skilled spend 81 total of 171
Skilled to gifted spend 111 total of 282
Gifted to expert spend 149 total of 431
Expert to virtuoso spend 188 total of 619
Virtuoso to fabled spend 315 total of 934
Fabled to mythical spend 383 total of 1317
Mytical to trans spend 450 total of 1767