Recovery weighting is a checked fraction of the remaining gap. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
A half recovery gives the dimmer row
With equilibrium 16, the slow row recovers 8 after the short wait.
21⋅16=8
A three-quarter recovery gives the brighter row
The faster row uses the same equilibrium and start, but recovers 12. The recovery contrast is 4.