Tomytec Bus System Configuration Problem

[hectorton]

I was not fortunate enough to purchase the "The Moving Bus System Basic Set A or A2 when they were first released.  However, I was recently in Japan and I purchased the System piece meal (Roadway, Power unit, and The Bus Collection Nishi-nippon Shatai Kogyo 96MC Non-Step Bus (5-Car Set) A2).  On arrival at home I configured the system to try it out.  To my disappointment none of the bus bodies for the Tomytec 5 bus collection that I purchased would properly fit on the bus system power unit. The bus bodies sit too low on the power unit and rub against the tires preventing the power unit from moving.  Am I missing something or am I installing something wrong?  As I understood it the 5-Car set is suppose to work with the power unit.  I can jury rig it and put something between the power unit and the inside of the bus body to raise it and prevent it from rubbing against the tires, but I should not have to do this; they are suppose to work with each other.  Does anyone have any info on the subject.  If someone out there has one of the original Bus System Sets can they take a look inside the body of the bus to see if something goes between the power unit and the body.  FYI, these are the HS Item Codes for the items I purchased (Bus Collection-231929, Power Unit-232124).