I'm not so sure it's the PW-X. It has the same characteristics as the older generation Yamaha drives, so I think it's just a 'spiced up' PW series drive. BTW I'm amazed that you can climb the 19% grade hill in front of your house. I guess you're in better shape than me. I climb that little 15% grade hill in Vufflens-la-Ville (which you probably know, as you lived in that area) and I'm already struggling.
It sounds like you're able to get a lot of range out of this drive & battery combo. I think that hills and a rather upright riding position have been pulling my range down. And, of course, the bike goes 45km/h which can sometimes be 'tempting'. I occasionally indulge myself in a little 45 km/h dash, but I've been reducing my average speed in order to try and gain a little range. In a certain sense, you guys over there in the US are lucky because the 20mph speed limit is a good compromise and forces you to 'save fuel'. I only had the choice between 25km/h and 45km/h, but after leasing, renting, and demoing a certain number of e-bikes I found that 25km/h was just simply unbearable.
Do you guys ever use ECO+? I'm struggling to find a use for it. The drive feels pretty much 'dead' to me in that configuration. I'm also struggling to see any difference between High and Standard.