I think from memory one of the aims of MRTF was to have CrossCountry to utilise one platform (if XC remained at 1tph). During covid it was a nightmare platforming-wise having XC overlapping across two platforms with double Voyagers.Is it for operational purposes at Piccadilly? The xx:25 Cross Country departure seems to depart to allow the next xx:29 arrival into the same platform & thus runs earlier throughout.
Reverting back to xx.30 was to add brake testing allowance at Slade Lane as TfW regularly lost time departing Piccadilly which led to late running towards Stockport/Cheadle Hulme which would impact other conflicting services.I don't know the answer, but it does appear to allow the Cardiff services to depart at xx.30 instead of a mixture of xx.31 and xx.32 departure times, which in practice mean little but make the service look a little more regular I guess.