I take the same stance as Lawrence - "ally" and "allied" have, unfortunately, 2 meanings.
One is as part of a definition of a particular troop type - the ally general.
but another is as part of a definition of a "foreign" contingent in an army - an allied contingent, it a contingent from an ally. The corollory is that this contingent is from an ally. This is the "common or garden" meaning of ally - the definition of a particular type of general is a technical one that applies only when specifically talking about a general.
the rules say that an allied contingent must be commanded by an ally general - but then the lists have a couple of exceptions where they are commanded by a sub-general!
However the allied contingent remains and allied contingent, IMO, whoever commands it, and the general can be accurately described as "an ally".
In this context the comment that an ally's baggage must remain with him includes an ally sub-general.
And as mentioned above IMO the sub-general classification is only to reflect increased reliability and nothing else.
However I shall mention it on hte list and see what happens!