Stitch Length Adjustment Accuracy?

[MtlBiker]

With a decent industrial sewing machine, how accurate is the stitch length adjustment usually?  I'm asking because one of my machines seems spot on... setting 4 gives me a 4mm stitch... 10 gives 10mm, etc.  But the other is fairly accurate at a setting of 4, but then it's completely off on the other number settings.  Maybe I'm being too much of a perfectionist, but this really bothers me.  And it means that if I want a certain stitch length (maybe to match something else) I have to fiddle with the setting back and forth until I get what I want.  My other machine is so close in the settings that I don't worry about it.  Should I be thinking of the stitch length adjustment as a relative number or absolute?

Am I expecting too much?

[chrisash]

It would help if you stated the one playing up, otherwise its a guessing game between 4 different machines you show on your signature

 

[MtlBiker]

29 minutes ago, chrisash said:

It would help if you stated the one playing up, otherwise its a guessing game between 4 different machines you show on your signature

 

Well, I didn't really want to cast doubt on the quality of a particular machine so I was asking in a more general way... Should I change my thinking to the numbers on a stitch length adjustment being relative instead of absolute?  Should I think a setting of 8 is just bigger (but not necessarily double) that of a 4?  Or should I be able to rely on an 8 giving a stitch length of 8mm and 6 6mm, etc.?