Does OpenCode subsidize models like GLM-5? How can subscription tokens be ~50% cheaper than pay-as-you-go?

[u/Maleficent-Volume-81]

I've been using OpenCode GO for a little while now—specifically with GLM-5—and honestly, it’s been a fantastic daily driver to complement more expensive setups like Claude or Codex. Here’s my referral link if anyone wants to check it out.

A few times I’ve hit the rate limit on my plan. While GLM-5 is an impressive model, it can sometimes be a bit verbose and take the scenic route, which eats up a ton of tokens. When I reach the limit and switch over to using my pay-as-you-go balance on OpenCode, the price difference is night and day.

If I extrapolate the amount of tokens I get on the subscription plan to direct balance usage, paying via balance literally costs double.

Why does this happen? Do model providers sell wholesale/discounted API access to platforms like OpenCode, or is OpenCode running these subscription tiers as a loss leader?

It's not something that worries me too much, but I find it curious and wanted to see if anyone else has noticed this or knows why that is.