As with any other module they should give the correct draw length if the cable and strings are twisted to factory specs. If yours are showing 3/4" long then something needs twisted up. As for that 28 3/5 feeling like 27.5"? How long you been shooting? Reason I ask is that less expereinced archers might not be able to tell much difference in the actual length. They rely on ancho references such as the string touching the nose when a difference in a2a and string angle can make this vary. I know that after 40 years of shooting compound bows I can definitely feel a difference of as little as 1/4", especially if it is on the long side. However I always shoot bows of approximately the same a2a and limb angle configuration.
If You're Not Living on the Edge You're Taking Up Too Much Space
Martin/Rytera Staff Shooter
PSAA Life member, UBP Life member
PADI AOW Diver