Do you mean multiple blocks or multiple specimens? The charge can be made once per specimen. For example, if you have 3 specimens, A, B, and C, you can charge 88344 X 3. However, if you performed the stain on 3 blocks of one specimen, for example, A1, A2, and A3, you can charge just once for 88344.
As far as I know, we haven't had any denials for multiple units of 88344 or 88342 when performed on multiple specimens.