In order to get the 4813 into a UPO you will need the version of this movement that has a high cannon pin. It is/was very hard to come by, with the only generally known sources being a member over on one of the other rep forums (who doesn't have any more stock), or Eurotimez, which is now defunct. I would also love to replace all my 2813's with the higher beat 4813, but keep in mind that the gen PO uses an in house co-axial movement that runs at 25200 bph, so neither the 2813 (21600 bph) or the 4813 (28800 bph) would be correct.