I am making the assumption from your posting that you haven't managed to get a "localiser established" call in on time due to ATC workload, so correct me if I am wrong there. In this case, and assuming (again) you are fairly close in eg 2000', personally I would take the glide anyway and descend from the assigned altitude. This gets you out of the "having to capture the glide from above" trap which is a pain. Many people will tell you that "this is not permitted in the UK, only in other european countries" which may be true, but then capturing the localiser from above is frowned upon also.
Every NATS radar controller I have spoken to, and my superiors have had the same feedback, is that they fully expect you to take the glideslope if they are busy with other r/t. OK, probably best not to do this from 4000' or 5000' where you have time to accept further assigned descents for glide capture, as ATC may be moving VFR traffic around underneath you. But close in, say 2000', I would never want to be in the late position of trying to capture from above.
I know this goes off the point of your thread and doesn't answer your question, but my operators have no such alt arming settings published for "capturing from above". All we would have in the window is the go around stop altitude.
Hope the assumptions I've made are not too far off the mark!