What is a milk rate chart?
The printed grid your union sends: fat down one side, SNF or CLR across the top, a rate in every cell.
Where a formula calculates a rate, a chart states it. The union publishes a grid, and the price for 6.4 fat and 8.7 SNF is whatever that cell says — no arithmetic involved.
Charts come in three shapes: fat against SNF, fat against CLR, and fat alone. The fat-only shape is common in Karnataka.
The awkward part of a chart is not using it, it is revising it. When rates go up by a rupee, every cell changes. Dairywala shifts the whole chart in one tap and refuses the shift outright if it would take any rate below zero.
You can bring your chart in as an Excel or CSV file, or photograph the printed sheet and send it — a person builds it and publishes it to your app, usually within about half an hour.