SUM in Informix 7.20 vs. Informix 6.0

Dear all, we experienced some calculation problems with Informix 7.20 4GL on SCO Unix 5.02. E.G. converting a cost value from Austrian Schilling to US Dollar requires a multiplication with 12.11, say 1000.00*12.11. This gave a result of 8900, whereas calculating 1000.00*12.10 resulted in 12100 and 1000.00*12.12 = 12120. This strange behaviour only occurs with i4GL and under Informix 7.20, not with iSQL or Informix 6.0. A similar problem was caused by the SUM within i4GL, when using SELECT firstvalue, SUM(anyvalue) FROM anytable GROUP BY 1. Sometimes (not always) this SUM would be wrong. Is it only us to have this problem? Yes, we are running Intel Pentium Pro 200, but an error of 30% is a little bit too high, right? TIA, Regards Kai