Is there are hard written rule on how to report semi-quantitative stain?

Our pathologists report "no staining" for semi-quant IHC's when the result is negative, I believe that's sufficient to support the billing--- the intent was there, and, technically, they did count, it's just zero.

However, some are questioning whether it is fair billing since there is no actually quantity (eg. the actually number "0" zero), what do you think? Do we have to make sure that they say zero "0"? Or, is there a better way of reporting negative findings for semi-quant IHC's to support billing for it?

Thank you in advance for your help.