My query was not to question if the business was able as undoubtedly it is.
The query was will they utilise those extra seats? I guess they will else why have the 321.
Obviously they will then be dedicated to specific services & as a worst case scenario slight problem for 23 pax on a u/s 321 as a flown in 738 replacement will leave 23 behind.
Probably me overthinking it...Anyways good news overall & almost certainly an uplift in seat capacity for the base then.