Commision Not Calculating Good

i installed the 2.2.5 multivender but i get ad the vendor this

balance_carried_forward: €0.00

_sales_period_total: €100.00

_total_period_payout: €0.00

_total_amount_due: €80.00

_total_unpaid_balance: €80.00



and its not calculating good 100 euro - 20% =83.33

What was a reason? Did u find it?