Cultural differences

Every international student at the Oita University has a Japanese student as a tutor. Our tutors are very friendly and very helpful. Still, there might be some misunderstandings between us sometimes.
For example, we wanted to buy cell phones with a prepaid card, although we heard that prepaid is dying out. So without our knowing our tutors phoned every cell phone store in order to ask if they offer prepaid cells. This must have been a list of 30 stores! If we had known that it would be so hard to find prepaid cells we would not have let them call every single store. Especially because they have to work and are busy. They just did it.
Another example: on the second day in Oita we had so much to do (making stamps, alien registration office, cell phones) and there was not so much time. After the alien registration they wanted to know what we wanted to eat. So we just had the idea of eating sushi. They agreed, but they did not tell us that the place was so far away and that it would take too much time to go there and eat. So on the way we realized how far and inconvenient it was, but the tutors just had followed our wishes instead of pointing out the distance and time pressure. So it ended with the mother of a tutor having to pick us up so we could buy cell phones in time and the tutor being late for work for 2 hours! She took us grocery shopping after buying the cell phone, but did not say a word about her work. If we would have known that we would have hurried up or shopped on our own!
All in all, we feel that the tutors do not discuss problems with us enough. It is as if they hide their wishes and needs and put ours above theirs. Or should we have asked them more specifically? Do Japanese never say that something is inconvenient for them? Or do Japanese express their wishes in such a subtle way that we did not notice it?