This is a good question and one that I'm not sure Motorola really considered fully when they first designed the ASK's.
In theory the ASK's are a good thing for system administrators - they give much more granular access controls to programming radios on trunking systems than the old style SK's which were obviously an all-or-nothing proposition. Obviously their features introduce quite a few roadblocks to the entheusiast community, especially when dealing with surplussed equipment.
In your specific case, some further information might prove usefull, but I'll give it a shot with some generalities. First off, I'm going to assume that the radio in question is authorized to be on all the systems for which it is programmed.
Now, the trouble with ASK's and other programming stems from the "Write Protect" option. From the CPS help file:
The CPS Help File wrote:Write Protection
(System Keys)
A Radio becomes write protected when written-to by a codeplug which contains an Advanced System Key that has its Write Protection feature enabled. Once a radio is write protected, it can only be written to again when the CPS has at least one Advanced System Key loaded (see the System Key Report) that matches one Advanced System Key being used by a Trunking System in the currently loaded codeplug, and there is at least one Advanced System Key physically connected to the computer.
Note: The Write protection feature can only be completely cleared from a radio by an authorized Motorola Service Center.
Both the latest versions of Astro (XTS/Astro Saber/Astro Spectra) and Astro25 (XTS5k, XTL5k, etc) CPS seem to support this feature in the ASK Administrator. In the "Define Access Level" section of the ASKA, the Astro25 CPS even has a preset called "Unlimited Access Without Write Protection". The Astro CPS does not have this preset (nor is the Write Protect feature documented very well), but it would seem you can create your own custom Access Levels, and use it when creating ASK's from the Master ASK.
Long story short, if you have a radio that is still being programmed with a mix of SK's and ASK's (a reasonable assumption as not all shops have switched to ASK's yet), then you would want to make sure that all ASK that are used to program the radios omit the Write Protect feature. This still means that you have to have the ASK for a certian system installed on the computer in order to make changes to that system, but if another shop wants to make changes to another system, they can do so without interference.
As I said, further information on the type of radio and systems might be usefull, but hopefully this gives you the gist of it.