To cut full width between the rollers, the LEFT and the RIGHT, between that.
You will need a cutter that can sensing the LEFT and the RIGHT.
The Cutting Head, it need to scan between the LEFT and the RIGHT rollers to know how what is the width (the distance ) of the cut area will be.
If you looking at your Cutting Head, if the Blade holder is on the right side of the cutting head, then the scan area of cutting width will give you more on the right, and the left will have some parking area for the cutting head when it scan on the left roller stop mark.
For Graphtec cutter for example the CE5000, it said it can hold 24" media but it only cut maximum media width of about close to 23" ( more like 22" rather ).
the Graphtec cutting head has the Laser scanner along with blade holder rather to the right of the cutting head assembly, and it is one of the cutting head assembly of a very small form factor, when compare to other cutter in the market. This gives the CE5000 of nearly 23" of scanned cutting width.
Other cutter may say 30" media holder, but it really can only scan 21" maximum width due to the fact that they need some space on the rail either on the left or the right to park the cutting head when reading the linear scan of the media width.
But if you suspect that you cutter is not reading or scanning media maximum cutting width properly, you may have a mulfuction sensory or pinch roller sensors may be damage. Some manufacturer have transponder on the left and the right rollers for the cutting head to detect the width between the rollers.