Worktop jig question

[foresttowndiy]

There seem to be many questions about using these jigs but I don't understand something.
All the instructions online say the rh and lh joins use the jig face up and flip the whole worktop laminate up for one side and laminate down for the other to get the opposing hands. Why not just flip the jig? The pegs go in from both sides so is there something basic I'm missing before I have a go?

 

[flameport]

The cut is always made from the left side of the jig to the right, starting at the postformed (front) edge of the worktop and finishing at the back. This means using the jig on the back of the worktop for half of the cuts.

If you flip the jig rather than the worktop, you would be cutting in the opposite direction with the cut starting at the back of the worktop and exiting the front. When the bit gets to the front it will rip a huge hole in the laminate.

Other things:
Measurements and position of the jig is critical. Check carefully, several times if necessary. You only get 1 chance to get it right.
The slot that the router guide fits into has 2 sides - the router is not a tight fit in the slot.
Hold the router to the side of the slot closest to you for all of the cuts. The cut line will look wrong - but once all the way through with the cutter at full depth, make a final pass with the router against the other side of the slot (furthest away) and it will be the perfect shape.
Make the 1st shallow cut with the router, then use a jigsaw to cut through the centre of that to remove most of the waste material. Cutting bits will last a lot longer that way. Jigsaw blades are cheap - router bits are not.