so alright, the parmakits start low, the way you are seeing it at idle. then at boosted RPMs before the curve hits, they advance, and then the retard back to about where it starts at idle, maybe a little bit more advanced then where it idles.
so to say, idle will be around 8 degrees BTDC for easy starting and idle, 2000 - 6000 rpms will be maybe 20 degrees BTDC, 6000 - 10000 rpms will be 12 degrees.
i've always had good luck with these even running them on stuff you aren't supposed to. maybe you got a bad one, but several people here who have used several of them vouch for them.
Also we've seen them make bikes run backwards when the spade connectors get flipped. don't do that....
The one that I'm running on my tomos that fully has a curve is numbered 82 48/19 which i read as part of the 82 batch of the year, produced on the 48th week of the 19th year of 2000. that would mean yours is batch 66 produced on the 25th week of the 21st year 2000. might be useful for tracking down a problem, but my guess is that you just aren't revving high enough to see the curve retard once it starts to move back.
also, a lot of timing lights are only rated to like 10k or 12k, which on these CDIs that fire twice every 360º of rotation equates to only accurate readings up to 5k - 6k which really just isn't enough.