Migration Variance payments usually appear when Tax Settings are not consistent between Lightspeed Retail and your Ecommerce solution.
When the total of a sale in Lightspeed Retail does not match the the total of the order in your Ecommerce solution, the Migration Variance payment method is applied to the discrepancy so that the order can download successfully to Lightspeed.
Please be sure to review your Tax Settings in both Lightspeed and your Ecommerce Solution to make sure that you are charging the same rate for each tax you collect on.
Additional Tax Documentation:
If you have any difficulty finding the root cause of this variance please contact Accumula Support with specific examples.