No, you cannot see the estimated range when plugged in other than the actual range but this doesn't help to see what the 100% is unless you take the time to actually charge it to a full 100% like we used to have to back in the day. This is chief among my complaints above. The other items are slightly annoying but not having any way at all to quickly get a range @ 100% is problematic since that's the primary indicator we use for overall battery health.
First, I agree some of the changes to charging screen in the car with the new UI end of last year I find a big step backward. Anyone with a legacy MS will tell you the size of the battery display is a fraction of the size it used to be with huge amounts of wasted space. I still long for the old v7 or v8 UI where there actually where up/down arrows you could use to toggle it easily to a fixed percent.
As for estimating range at 100% SOC, but you can get a really decent estimate of range at 100% simply by taking the indicated range at the end of any charging session and dividing by the percent SOC. I know some will strongly argue I'm clueless, but I've done this to track apparent capacity on my mid-2016 MS90D for the past 6 years since I purchased it new and took delivery at the end of June 2016.
There are a couple things with will help minimize the numerical error in the calculation. One is of course it's less prone to rounding if you're charging to 80% or 90% and not say 50%. The other big factor is to let it fully complete charging and stop by itself as opposed to just unplugging while it's still charging. That's due to rounding errors that SOC is only reported in integer of 1% increments, not fractions even via the API calls, which depending upon the car, could result in a +/- 3 mile numerical noise. Being the number nerd that I am, I also pull all my data via a logger program I leave running on my laptop to continuously collect data, similar to what some do with various apps. This gives me the range values to two decimal points, which add precision, although I agree not necessarily much in way of accuracy.
Now I know some will tell me this is totally inaccurate and you can only get it by charging to 100%, but my data set of roughly 1250 charging sessions over 6 years would say otherwise. Below is a plot of estimated range at 100% over that period. Scattered through that plot are 21 times I've charged to 100%. I'd challenge anyone to pick out those 21 points from the other 1230 or so. I've done this highlighting the 100% SOC points on the chart and they fall right in amongst the scatter of the rest. Most of the outliers actually result in being points where the car did get unplugged before charging shut off, car was only charged to relative low SOC, or I ended up having to pull values from the app vs. my logger program which has less fidelity due to number of significant digits. All those things add to numerical error in the calculation and create more scatter in the dataset.
You might observe that the level of scatter the last 10-15k miles appears to maybe have increased. Part of this is due to the fact my car will go ~3 months at a time without being driven as I spend most of my time overseas at the moment on international assignment. I find it takes doing a couple longer drives and charging at times for things to become a little more consistent after I've not used the car for 3 months. But once I get 200 miles and a couple charging sessions in the seat, it stablizes back out. I attribute that to the BMS calibration needing to stabilize a bit after periods of inactivity.
And as the saying goes, your mileage may vary ....