I would say that relying on that can be a risky strategy because CZ does negotiate fares with a number of TAs so you could end up booking a fare which 'looks' almost the same but has, in fact, different ticket conditions. All OLTAs have phone numbers and I would personally always call and ask to confirm ticket conditions and booking bucket (as irishguy28 rightly suggests, have a handy printout of eligible booking classes at hand that way you know right away whether that good fare would cost you those level miles and segments).

That said, I can almost certainly guess right that if you have seen a great economy fare on CZ, it will NOT earn you or your husband any level flights/miles as the cheapest CZ economy fares are excluded from accrual.