vx d15z1 timing

i have to slam dist to get it to 16. is it off a tooth? timing marks look right. 103 belt. anyone else timing like this? all original. stock everything. no mods.
D15B2 = 107 teeth
D16Z6/D16Y8/D16Y7 = 104 teeth
D15B7 = 106 teeth
D15Z1/JDM D15B = 103 teeth