I agree with Brendan. My workflow has always been to do an original transcode of the AMA files to a high resolution, 145 or 220. Then from that footage, do a transcode down o the 45. The final relink to online the project should be to the 145 or 220 footage.
Also before doing the transcode from the 145 to the 45, be sure to give source tape names as this allows for an easier relink.