1. Conventional legacy phone systems do not use, do not transmit and do not understand the '+' symbol. The only characters supported are 0 to 9, * and #. The '+' is intended for human use to give a universal way of writing full international phone numbers. Some equipment is capable of recognising the '+' symbol and either acting on it appropriately or converting it into the correct characters in the [0-9,*,#] set that subsequent equipment needs.
2. As I wrote in the first reply, if OBi's Call History is showing SP1(01181123456789) then that is what it is sending to GV. If GV is then mangling that to something else, then either GV does not want 011 as the international access code or it has some other bug. 811 234 5678 is a NANP (North America Number Plan) number. That would indeed have given you a different ring tone than the usual Japanese one!