Mandatory reconsidertion?

Hello, I'm looking to get some advice following the result of my PIP renewal. I was originally sent the form in April but the DWP but was given a very long extension from a kid hearted agent due to my struggling so much to fill it in. My deadline WA 24th August I sent it back by next-day delivery guaranteed on 18th, the following day I received a text from the DWP to let me know they had received it then the day after that on the 20th I received another text to let me know my review was complete. I received my letter outlining the DWP's decision approximately one week later. Basically it turned out they kept me the same but I spent hours upon hours filling it in because it was so hard and so involved. Also my mobility issues have worsened due to my chronic fatigue becoming 100 times worse. I looked through it and they didn't score me correctly although I did scrape through with just enough points for the higher rate on the daily living component even though, looking through the points they gave they didn’t score me properly for everything. They seemed to be giving me as few as they possibly could but still got the higher rate so that's OK. However as they used this same few-as-possible method on the mobility component as well I got the lower rate. When I worked out my points and how they should be scored myself I got the higher rate. I explained in detail how I hadn't been to an unfamiliar place at all in over two years as it causes too much distress and now amount of prompting helps me to do it, and that I only stick to places I know and they scored me for needing prompting to get out. I also explained that, due to extreme chronic fatigue (sometimes I have to hold on to the walls of my flat to get around it without collapsing) I ticked 'can stand and move for 20 meters but no more than 50 meters' but they scored me for 'can stand or move for 50 meters but no more than 200 meters'. I'm very curious now as to why and how they did this especially as they admitted in the letter that my condition had changed and that they were awarding for a longer time (they also didn't say how long the award is for) Is it worth me asking them to look at it again as it seemed rushed? Or is the risk of losing the whole award too great? I was told my own disability advisor a while back that the risk to too great and by another that it is a very small risk. As it's been nearly a month now since the letter arrived I'll have to be quick. Couldn’t post this before as I've been in such a bad way. Could I at least ask them to explain how they came to this decision? Would I have time to look over that information and then decide whether to not to ask for a reconsideration? Thanks so much in advance for your help.