Note: Usage efficiency is most useful on a week to week basis. Interpreting usage efficiency over larger periods of time can give a sense of performance over that larger period, however, it will take into account good and bad efficiency without that context for the user.
If you see a Variance item showing a 0.00% Usage Efficiency, it could mean that this item has an Actual Usage and no Ideal Usage for the item or an Ideal Usage that is not properly configured in Decision Logic, therefore it will not have theoretical usage efficiency reporting.
It could also mean that the Actual Usage was so high that the Usage Efficiency would be extremely low.
For example, if your Ideal usage of lemons was 225 and your Actual Usage was 520, your Variance is larger than your Ideal Usage and your Usage Efficiency would be in the negative percentages.
N/A for an Item
If no usage efficiency bar shows at all, and you see the text N/A, this is because the item is not tracked in the DL system or does not have data for actual usage.