There are a few reasons your range prediction could rise dramatically including warmer temperatures, efficient driving, new software updates, less use of climate control during the most recent driving. I certainly wouldn't be alarmed.
To determine your range you can download WattCat that provides the actual kWh in the battery or use the simpler, yet accurate, method of dividing the number of miles traveled by the amount of decline in the SoC and multiply by 100. For example, if you traveled 140 miles and used 70% of the battery, you managed 2 miles for every 1% of the charge for a range of 200 miles. I reset one of the trip odometers every time I charge the car which makes tracking my range very easy.