No it hasn't, it's gone up by about $30 - its $590 this year last year was $560 from memory.
Actually, I am wrong and you are right.
For some reason I thought Full Membership was $620 last year.
I just checked invoices.
Silver was $420 and I had to pay $155 for upgrade which makes it $575.
That means it has gone up $15.
Stupid me spreading false information.