Modding
I think there is a way:
I recently had to clean my TE-11WZ eyepiece after a windy day on Titchwell beach which caused some sand to get into it, so that when it was twisted up it made a crunching noise. On unscrewing the rubber part and pulling off the rubber, I found that a few small screws hold the plastic twist-up piece onto another piece of plastic that is then screwed onto the eyepiece. I unscrewed them (being extra careful not to lose them), separated the parts and cleaned them up: no more crunching sound.
On re-assembling it, I noticed there was an extra slot in the plastic, effectively another level of extension, that wasn't being used because of where the screws were attached, so I put one screw through another pre-existing hole so that the extra slot came into play. From then on I've been able to get a little extra extension which works better for me.
Sorry this is a bit vague, as I'm recalling from memory, but if you're okay with a little hands-on modding I assume your eyepiece could be changed too. Obviously caveats apply, I assume the warranty may be voided if you break it, so you will have to accept full responsibility for any changes you might make.
A final assumption of mine is that Kowa limit the extension for reasons of robustness; at greater extension there is less plastic holding the two pieces together and it could be more likely to break, but I accept the risk for the benefit I get.
Hope this helps.