VSTO add-ins some times irritates us by causing delay. No work around works for it and atleast a clue will not be available for us to work on that. It works fine in some systems. It loads slowly in some other systems. Some times, it even does not load in some systems. 30 second dealy, slow start-up, checking for certificate, publishing problems etc. comes under this domain.
Forums are the best places to get solutions to this kind of problems. Ofcourse, obviously almost every programmer will be going through Forums, especially VSTO programmers.
These are the links from forums for those who are sufffering from lazy add-ins (loading slowly) problem. These are the dicsussions on the delay problem. Hope this helps!
A very technical (related link)