@Hello
I think there are a couple of mathematical issues with your plan:
You have not spent any XP on Evasion, but your spreadsheet shows an increase of 5 levels.
DADA: You spent 40 XP, and this skill has a 1.3x modifier. 40 * 1.3 = 52. Levels 11-20 are 20 XP each, and we started at level 10, this should be level 12.6 not level 15 (10 + (52 / 20) = 12.6).
Dark Arts: You spent 20 XP, and this skill has a 0.2x modifier. 20 * .2 = 4 XP. Since levels 1- 10 are 10 XP each, and we started at level 0, this should be level 0.4 instead of level 2.
Once these issues are fixed, I think our plans are very similar. You have chosen to specialize in Transfiguration whereas I chose a more balanced approach across magical skills. Dumbledore's best subject is probably Transfiguration, but he is also very good at pretty much every other subject too. I would personally prefer to be a bit more well balanced across most subjects, and then choose a specialization or two as Harry's character develops.
If you really want to specialize in Transfiguration, I would allocate 210 XP to Transfiguration. This would get Transfiguration to level 20 and would leave 50 XP to apply to other skills/attributes.
I would also reallocate the 20 XP in Dark Arts, since it has a huge 0.2x negative modifier. In my opinion, it doesn't make sense to spend XP on the magical skills that have negative modifiers at this time, especially since negative modifiers will likely increase over time. For Ancient Runes, Arithmancy, etc, I assume the modifiers will increase if we decide to take those classes. For Dark Arts, I'm not really sure how we'd increase the modifier, unless we do some extra curricular activity.