Can’t believe I’m replying… 😉
Theory makes sense, swinging side to side is sometimes easier to use (and good for the abs!)
In reality, our flymo was a terrible purchase. Blows grass everywhere, even a ‘collector’ one, motor blew up after little use and was going to cost more to repair than replace the mower! I also found it blew the grass flat, then battered then ends off it, rather than cutting it.
Also, bear in mind that the flymo rides on an air cushion. If the bumps are really bumpy, it will ‘spill’ all it’s air cushion and still scalp the tops of the bumps.
I got a Bosch on wheels and it’s miles better.