My 244**** 90mm Elmarit should be optically the same as yours.

I certainly wouldn't describe it as being prone to flare (about the same as a Zeiss-Rollei HFT 85mm, which should be among the best in that parameter).
I'm not sure about it being single coated either. In any case, it certainly *does not* have low contrast pastel colours!
It's generally a very high contrast/high acutance lens and one of the best short teles I have (I have quite a few): I very seriously doubt that the VC would do better in the corners, despite any "APO" labels...
In fact, several tests I read say the VC is actually fairly prone to flare.