ARC amps and 6550C Winged "C" small pins

Has any ARC amp owners experienced loose tubes in the sockets after replacing old 6550C Winged 'C' with new ones. The old tubes are snug and tight. The new ones fit quite "loose". Tubes came from Upscale Audio and were Cryo'd. However, i have ordered some 6550C from The Tube Store a few months ago and the pins were smaller than the originals i purchased in Jan. 2004. My Amps are Classic 120 mono's with GNSC Ref Upgrades. If those tubes were mounted horizontally in any of the VT series amps they would likely fall off.
What an odd thing. Tightning the little metal flaps in the tube sockets with a tiny jewler screwdriver is not very effective.