By my calculations and based on a limited number of anecdotal observations, it looks like the Bluestar 10/13/14 group of services now needs 8 vehicles to operate off-peak, up from 7. This isn't so much to do with the 10 running a different route, but rather extra time allowed for the 13 and the 14. The 13 is now retimed to xx10/xx40 with a 1hr05 round trip off-peak (was 1hr) while the 14 is now allowed 1hr35 round trip off-peak (was, IIRC, 1hr30).
Essentially, the 13 which arrived at xx03 used to then form the 10 at xx13 in most hours, but now the equivalent 13 journey effectively arrives at xx15, so it cannot form the 10 which departs at xx10. From one observation only (and I don't know if it applies every hour), the 1210 on the 10 is formed off the 1200 arrival on the 14.
Good to see reliability playing a part in scheduling, even if that does increase vehicle requirement.