My 90% SOC recently dropped from 206 to 202 miles after I hit 15k miles. That translates to a drop from 226 to 222 on a 100% charge. I may have charged up to 100 about 3 times till now and never let it drain below 10%. I mostly supercharge as I don't have the convenience to charge in my garage yet. Do these numbers seem right for other Model X 75D owners. Mine is Dec 2017 build.