calculating total stock based on variations

We have a shop that sells flour. they sell it in .5kg/1kg/2kg amounts. We want to use variations for this (we have additional packaging variations)

We have tried Measurement Price Calculator which is a plugin that will control stock based on the amount sold. However this plugin will not work with additional fixed costs for packaging variations.

We want to go back to variations. However our issue is if we have a 20kg bag of flour we want something to calculate the stock as well. I.e we want to calculate stock based on selling .5kg bags, 1 kg bags and 2 kg bags out of the same stock. Does your plugin do this?

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