If you take your basal body temperature at a different time than usual, don't try to re-calculate it in any way (even though you may sometimes notice patterns and find formulas and methods for re-calculating temperature taken at a different time than usual). OvuFriend does not recommend using these methods, because there is no reliable way to correct the basal body temperature (BBT).
Each woman's body is unique. There's no way to predict how taking your temperature at different times will affect its measurement. Some women's basal body temperature does not change at all over time, but in most women even a one hour deviation has a significant influence on the outcome of the measurement. Temperature can fluctuate in both directions, increasing in some women and decreasing in others.
So, if you take your basal body temperature at a different time than usual, don't try to re-calculate it. Instead, check "ignore this temperature" (located just below the "temperature" box). One or two rogue temperature readings should not affect the interpretation of your cycle. (When should I check the "ignore this temperature" function?)
You may also want to read about factors that may distort the reliability of your temperature measurements.