API throttling limits and reason codes

I’m going to be running on a service account for some bulk importing into contacts. I’ve got the 429 reason code for sending requests too quickly, but don’t know the reason code for overrunning the per-day transaction limit. Two questions:

What’s the service account limit on per-day transactions?
What’s the reason code for overrunning it?
A third question: why is it so hard to find this stuff out?

Thanks

Frequently Asked Questions - Keap Developer Portal under throttling.

Also each response has headers indicating throttle stats. API Token Quota and Usage Measurements - Keap Developer Portal

We are going to be doubling the limits on PATs/SAKs shortly.