'missing' entries post 1733 can sometimes to obtained from the Bishops Transcripts - though some years (not all and not 19th C) are on Manx Museum film I don't think they are on Mormon microfilm - also not all years/parishes have survived (see my comments re Marown on manxnotebook transcriptions)

The BT's are useful when a register or some pages have gone missing but no use against clergy who were incompetent (or too drunk or senile) to attend to the register as the BT's are also likely to be deficient