It was far from pretty but Munster will not have been too fussed as they secured their progression at Temple Hill.
While they closed the game out comfortably, the lopsided scoreline was a tad deceptive because it took 44 dour minutes for the first points to be registered, Scott Deasy slotting a penalty with the final kick of the first half.
And that was with the home side down to 13 after Sean Dougall and James Cronin were sent to the bin.
It was hardly a game to warm the hearts of those who braved the bitter cold, but the quality improved substantially after the interval. Munster, with the full complement restored, upped the ante and parked themselves in the visitors' '22' for the majority of the second period.
Corey Hircock, on for an ineffective Luke O'Dea at the break, ran over for the opening try, crashing over in the corner in the 56th minute.
Deasy, on familiar ground, was unlucky with the conversion but the eight-point gap was never one that a lacklustre Plymouth were likely to recoup.
The red machine continued to pile on the pressure and CJ Stander went over for a second try with Albion down to 14 after Jack Andrew went to the bin.
Deasy added the extras via the post, and although they didn't score again, Munster had few problems sealing top spot in their group with five wins from six, although they missed out on home advantage in the quarter-finals.
Munster 'A' – J Murphy; R O'Mahony, D Barnes (D Sweetnam 63), I Dinneen, L O'Dea (C Hircock ht); S Deasy, C Sheridan (B Haugh 77); J Cronin, D Casey (N Scannell 62), C Condon (A Cotter 53); I Nagle, D Foley (B Hayes 69); Dave O'Callaghan, CJ Stander, S Dougall (R Murphy 72).
Plymouth Albion – R McAtee; L Warner, K Fislau, B Armitage, T Bowen; R Cushion, P Rowley (P Bailey 75); J Andrew, DL Cowan (D Salter 71), A Brown (L Fairbrother 71); H Tovey, W Carrick-Smith; R Nasiga, A Carpenter (H Stupple 57), S Hocking.
Ref – R Thomas (Wales).