I thought the "sepia" tint you see is maybe from Umbrous? He has very dark ears compared to my lot, but then they are not amazing show specimens, although their relatives are. Hex is definitely Umbrous I would say so seeing Ponder will maybe help us decide...
Grey, Silver (SgSg)
Top Coat Soft pastel grey, carried approximately one third of the way down
Undercolour Mid grey
Belly Fur Dull White
Crescents White
Ticking Lightly and evenly ticked with brownish black
Chest Band Brownish black - not solid but concentrated ticking
Cheekflashes Black - not solid but concentrated ticking
Eye Colour Black
Ear Colour Dark Grey
Sepia Grey (Sgsg) is the heterozygous form of Silver Grey, and retains a variable amount of yellow pigment in the coat. There is an interesting
article by Lorraine Hill for the California Hamster Asscociation Newsletter you may want to read.