Let's see, here's the last TRC-diff-switches:

2542.17 x4

10168.683 x4

40674.735 x4

162698.94

Sure, on Bytecoin it needs more blocks to raise the difficulty, but it also needs more blocks to drop, so it's basically the same problem.

If the max is 4x how can it jump so much in one day?

The other day it was 6 digits diff and then the next day it was double digits diff. For bytecoin that would take on average a week or two between diff changes, so a large swing is not as possible so fast.

is the only difference TRC is 4 times faster? I was under the impression is wasn't just the 4 times faster blockchain that made TRC different.