Sounds right, especially under those driving conditions. I'd take it out of sport mode for a week to lower those RPMs. Also check your tire pressure to be sure it's where it needs to be. People often overlook the simple stuff.

Are you running mid grade fuel? 87 octane burns faster, I run 89 in both of my BMWs and get no knock and predictable mileage.

Also, consider a transmission filter/fluid swap. Be sure a competent person or shop does it, and hopefully they have done it before. I used a BG machine to do my exchange, and the OEM "lifetime" fluid was toast. I just did mine on my 01' 740il and it feels more solid. With you driving on hills I would do this for sure. I think the filter kit is about $80 and then you'll need Valvoline Maxlife x Xqts. Only use OEM filter. (FILTRAN) Im not sure how many the X5 holds, as Ive yet to swap the transmission fluid, but it's next on my list.

Try to keep your foot out of it, even though it's fun.