Can transaction value plus gst cross mrp ??

You have to fix your transaction value adjusting to the rate of tax i.e. GST at whatever the percentage it is, say MRP is Rs. 100 Transactional value should be Rs. 88 and 12% GST of Rs 12 adds to the product, However in the case of medicine the MRP of the medicine can be fixed by a difference of paise i. e. Upto 99 paisa.

So in any case total invoice value should not cross MRP. Am I right ??

So in any case total invoice value should not cross MRP. Am I right ??

Yes, the total invoice value should not cross MRP