Hi,
Why the other condition is coming as inactive i.e. with yellow mark i.e ZR00, ZSER & ZSBC.
You need to check the condition class for all these condition type i.e. ZR00 as Price, ZSER as Tax, ZSBC as Tax (also for other tax consition) and ZR01 as Discount and then again maintain the condition record fro ZR01 in VK11 and run the test cycle its will resolve the issue of calculation.
Tell me one thing there is no SD resource in your project reason y I m asking is this is something which is very critical to business and both SD & FI need to fix it for business. It not the area which FI will take care. See there is no harm in learning but that need to be done under some who know the stuff well so that if any thing goes wrong he will guide you then and there.
Anyway make the above changes and run the cycle its will resolve your issue.
Thanks.
Sumeet