[TUI] $ spent in context decreases after request

[artemkalugin01]

Description

I experienced 2 issues with unreliable $ spent in Context block.

Issue №1: Without model(Sonnet 4.5) change new value in $ spent sometimes decreases by a small amount after message processed(~$0.10), can provide no steps on how to reproduce, seemingly random requests.

Issue №2: After changing model from Sonnet 4.5 to Haiku 4.5 and running first message $ spent in context decreased by ~$2, while billing in Zen seems correct (screenshot attached)

Models: Claude Opus 4.5, Claude Sonnet 4.5, Claude Haiku 4.5.
Provider: Zen

Plugins

OpenCode version

1.0.220

Steps to reproduce

1. Have open session with Claude Sonnet 4.5 selected.
2. Change model to Claude Haiku 4.5

Expected behavior:
Amount in $ spent increased by correct amount

Actual behavior:
Amount in $ spent decreased by ~$2

Screenshot and/or share link

Operating System

macOS Sonoma 14.1

Terminal

iTerm2

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• Around $30 just disappeared from my Zen account #4160: Around $30 just disappeared from my Zen account

This appears to be a recurring issue where spending values displayed in the context block don't accurately reflect actual charges on the Zen account, similar to your experience where the $ spent decreased after changing models. Feel free to ignore if your case involves different specifics.

[artemkalugin01]

Replying to @github-actions
Issues #3171 and #4160 seem to be related to my problem although there was no info on decreasing spent amount, only about incorrect billing overall.
Hope I provided some additional context with this issue

[EthanShoeDev]

My spent figure dramatically increased: https://x.com/ethan_shumate/status/2008654158342353145?s=20

I did switch models many times throughout this thread but I think the miscalculation is not always in the negative direction.