Companion and upgrade advice please!

Help me please, wise gurus!
I'm looking to get the Dragon clan to Lax next summer and need a bit of advice. My understanding was that if I purchases a qualifying revenue fare (either B,L or Y) and used the companion voucher issued by MBNA to take another passenger with me for "free" I could also use 20,000 to upgrade the revenue fare to PE (or to UC for even more miles) AND use the PE upgrade voucher to upgrade the companion fare to PE.It was my belief that this was the only time a companion fare could be upgraded.FC seem a bit mystified and have said they'll call me back today when they've talked to "somebody who'll know" (could that be somone we might know on here ??).Have I got this wrong?
Thanks DL
I'm looking to get the Dragon clan to Lax next summer and need a bit of advice. My understanding was that if I purchases a qualifying revenue fare (either B,L or Y) and used the companion voucher issued by MBNA to take another passenger with me for "free" I could also use 20,000 to upgrade the revenue fare to PE (or to UC for even more miles) AND use the PE upgrade voucher to upgrade the companion fare to PE.It was my belief that this was the only time a companion fare could be upgraded.FC seem a bit mystified and have said they'll call me back today when they've talked to "somebody who'll know" (could that be somone we might know on here ??).Have I got this wrong?
Thanks DL