Agreed but in our case this is due to tiny rounding differences in tax and per-unit price. With only four decimal places at the stock level there is no getting around it.
I suppose some sort of manual GL Journal entry would fix it but it will always exist as we move on with business transactions.
You can see the differences below:
We only have two decimal places for USD but costs and taxes use far more so we will always have a small discrepancy. Our stock per-unit cost/price uses all four decimal places and even that is not enough to produce cost/price matches in all cases. Z_CheckDebtorsControl.php shows small (but matching) differences for every period.
So far tax has caused us the greatest pain as whether we were to round up or round down we we always have a small difference.