Same models do very somewhat but not like the drop you have experienced.
I will mark or grade my mileage (vs. others) when riding long routes or in packs together, that way we are using the same fuel, same ride etc. So for ships n giggles, if I put in 4.32g I will either ask of looky at the other guys pump and make a mental note. Ugh.. he took 7/10 less than me.
Last season, Mike (Wine Guy) toasted me at every fill-up, I was on my '09 FJR then. We gauge at every fill-up, maybe more so cuz we're just bored and need some jibber-jabber while putting our gloves back on. I was always eating about 3/4 more (gal) at each fill-up than he was. I chalked it up to two things; I'm a little harder on the twist-up and he has a Gen3 (2013). For SE Ohio/W.Virginia a couple of weeks ago, we rode down, day looped, and back home together and measured again upon every fill.... hehe, I've now got the better mileage by about a 1/2-3/4 gal at each fill-up. It's not huge, maybe more entertainment between friends.
Yes it's nice to flip the tables, only problem is... I need to fill-up about 5,000 more times to offset the higher cost of the BMW torque monster