Checking balances calculated by Koinly against the actual balance on your wallet/exchange is one of the best checks if everything imported correctly - we mention it in Section 2 of How to ensure your tax report is accurate.
If, after importing your data, the balances of assets in Koinly are different than what your wallet/exchange says, it usually means that:
Some data was not imported
Some data was imported incorrectly
Check the article below for more details about this error and how to deal with it: