Just a quick question - by accurate do you mean one strip is not the same width as another - or it is not the same width from one side of the strip to the other?
I always cut on the generous side. If I need 2.5 inch strip - I cut so the the line running at 2.5 is totally on the fabric - not so far however to actually show the fabric - does that make any sense? I would rather trim off a "hair" than have to worry about a seam allowance that was too narrow.
In all reality, as long as you are consistent - you will be fine.