I've used my new E31 about 6 times and each time it created a map. Sometimes the maps were quite good, at other times not very good. However, today I used the mopping feature and no map was created at all. Does this reflect a problem with my machine? Also, can anyone answer the following question: if I bought an E30 for upstairs, could I use the mopping accessory from my E31 in the E30?