I don't have time to scan the AIP, and I suspect that I will get jumped all over for this, but what the heck! .........
Was not the "maintaining" introduced by ATC when calling Centre following a frequency change, when on radar?
ie "Centre, XXX maintaining 8 thousand"
however, it is not required in a full position report
eg "Centre, XXX (was) Bongo (at) 35, 8 thousand, Richmond (at) 04"
I guess you can leave the "was" and the "at's" out, but does it really make any difference?
If "maintaining" is creeping into the full position report then its probably because of the above!
Dr