Are you measuring from A to A or A to the B+ centertap?
There can also be a deviation in DCR readings between transformers, if they are from different manufacturing lots.
That is normal, the layered winding technique means that one side of the primary will have about 15% to 20% more wire length (thusly resistance) than the other side. Each successive layer has a slightly greater radius.
This phenomenon also is measurable on the Z565, and most PP OPTs, except for the higher-cost ones with bifilar primary windings.
The A470 has layer wound primary windings, and bifilar wound secondaries.
Refer to this:
http://diytube.com/phpBB2/viewtopic.php?t=3694
I had one Z565 which had one side of the primary measuring at about twice the DCR of the other side - that is the one that "Geek" used for the Z565 autopsy / post-mortem.
/ed B