biggest tele2 sąskaita ever

so my cell phone bill for january is 81 lits. they've generally been 40-60. why the jump? partly because of master's classes, which take some organizsation via the phone to get straight what when and where. however, the biggest jump is a 44.8% increase in sms, up to 391. This is intersting. It's due to about ten days of romancing my special lady at the end of January. Is this increase arithmatic or geometric? If it's arithmatic I can look forward to about 670 sms this month. If it's geometric, 822. If it's exponential, God help me...