Claude /fast mode consumes money fast

I got a $50 credit from Claude for the /extra-usage command which I turned on and cleared context and had it debug a particularly thorny issue related to a C app conversion to swift with lots of external resources. While it didn't solve the issue (I switched /fast off after two rounds), I think it got me far enough to solve the problem with [regular] Claude. After the first round it used $17 of the $50 and after the second issue to fix/diagnose it used $35 of $50. This isn't a complaint and I might use it more on focused, targeted debugging/solutions - or getting me there quicker. I enjoyed the speed. It's not blazing but as they say I can see a 2.~ speedup. I just need to beware that my deposit will go quickly. Just some thoughts after using it.