Actually NRR is exactly for making sure that the message arrived intact, either as a protection from transmission failures or from security breaches (e.g. man-in-the-middle attack). It might be pretty bad if I ordered 2 items and there was a transmission failure and it got changed to 1,000,002 (actually it would be more binary than that). The signature assures the To Party that it did not change and NRR assures back to the From Party that it did not change (round trip). David Fischer Drummond Group.
