It used to be more common, but with long acting meds having some statistical evidence of having less substance abuse issues, it makes little sense to prescribe truck loads of short acting medications. Sometimes, due to insurance restrictions (eg. will cover MS Contin at BID dosing only or restrict fentanyl patches to 10/month even though some patients are in full withdrawal every third day, or won't cover any long actings at all), then ya do what ya gotta do...
But for the most part, using multiple short acting drugs is not indicated. If patients have variable pain, then they need lattitude in how the medications are taken or half the tablets routinely, etc, rather than more than one short acting med. It gets very confusing to the patients to have multiple short acting meds and also sends a message that there are virtually no limits on what they can take when they want to take them...