modifier 30 vs modifier QX

Hi, I am new to the billing area and am billing for 1 CRNA, who works as an independent practitioner at an ASC. I am having problems with my Ohio BWC claims getting rejected on the basis of modifiers. I was using either QZ (for general) or QZQS (for MAC). They told me I cannot use these and must use either Modifier 30, QX or 23. I noticed on a few claims that they did pay that they had changed my modifiers from QZ to modifier 30. Whe I spoke to the today they suggested I use modifier QX. AM I correct in that this modifier will pay less? Is there a different meaning for modifier 30 than the one I have--what I have shows that it is used as "A consultation service during medical legal evaluation"? HELP PLease.
Thanks,
Diana