VM2 calculation rules doesn't work

[stvnmth]

My problem is with the Virtuemart 2.0.18a version. Everything is okay, but the calculation rules doesn't work. I set one rule for the VAT, and switch type 'Tax per product'.
When I set another rule, this not work in any type of arithmetic operation.
Maybe this is some bug in this VM version? Or I missed something in settings? Another previous version of VM, this feature is worked good.