No, the situations are exactly the same. It's a 2/1 overcall in which you have a singleton in an unbid major. The scoring is different- one is MPs NV, the other is IMPs Vul. If the decision on both is based on venue, say so. Me, I don't buy it. On the one hand, Match Points gives you a little more leeway when NV. On the other hand, -150 is probably a loss of 1 or 2 IMPs, but darn close to a 0 in MPs. I would not feel more comfortable if partner raised me to 3♣ on this one if we were NV in MPs than if we were Vul in IMPs. Partner knows the scoring too. Overcalling 1♦ is not the same as overcalling 1♠. Also, a holding like QJ98x is much more offensive than AKxxx (though obviously AKxxx is a better holding).