I think it is more likely that they are trailing spouses and not on expat packages, but then again who knows?

While it is possible I don't think any company with prudent practices will second a PA on expat terms unless you are for the owner/founder/chairman/president of some MNC or a tycoon/billionare. Budget and work visa quotas are simply better allocated to execs who can contribute to management, revenue and governance.

Not to disparage the TS, but I'm just saying be weary and negotiate smartly. All the best and hope that the offer works out.