Either I'm doing something horribly wrong, or the RNG hates me more than usual today.
I used unupped Flying Weapons for reasons stated above. I substituted 1 unupped Crusader and 3 unupped Shards of Patience because I don't have enough of those cards in upgraded form right now. This is the resulting deck:
My first ten duels in the Platinum League resulted in a record of 1-9, which is a very long way from your 9-6. I have difficulty believing that 4 unupped cards made that kind of difference.
First Ten Duels:
Loss - Reverse Time
Loss - my own Arena deck
Loss - RT + Ghostmare
Win - mono-Life
Loss - Pulvy + BB
Loss - Procrastination + RT + Ghostmare
Loss - mono-Aether - Silence on first 2 turns, then as often as possible
Loss - deckout b/c Miracles
Loss - Ulitharid x2
Loss - mono-Air