Workflow Link and Revision Update

Right now I've been experimenting with two Workflows. One for our everyday purposes, up to release to production. Release to production then has two branches, one goes to Obsolete, and the other links to another workflow, in this case ECO Workflow. At this stage the part has gone from numbers revs to being approved, and when released to production, it goes to REV A.

Once it switches to the ECO workflow, at the approved stage i have set it to set variable, next rev and then Inc. revision. And in the workflow state I have it set to increment 1 alpha rev. When i get to this stage my rev goes from A to K...can anyone explain this?

SolidworksSolidworks Pdm enterprise Pdm