Execs are prevented from building up Euro credits unless the execs themselves collect the tickets. That means that unless the exec himself went to at at least 2 of the CL group away games then he cannot guarantee you tickets. As soon as an exec allocates their ticket to someone else a new membership number is created and the credit is placed against that rather than the exec. You need to find out if the exec has been to any Euro aways himself this season, it won't count if he allocated them away.
This basically means that if the ballot is oversubscribed (and it will be certainly), then the ST holders and execs with Euro credits will get tickets first, followed then by execs without credits.
I have 5 execs and a lad from the newbs used them for Benfica, but as I didn't collect one myself there was no credit, the credit instead went to newbies newly created membership number with MUFC. When the Basel game came around I didn't get a single ticket in the either ballot.