Increase a date with a certain amount of months.
Source position: datih.inc line 139
| procedure IncAMonth( | 
| var Year: Word; | 
| var Month: Word; | 
| var Day: Word; | 
| NumberOfMonths: Integer = 1 | 
| ); | 
IncAMonth increases the date as specified by Year, Month, Day with NumberOfMonths. It takes care of the number of days in a month when calculating the result.
This function does the same as IncMonth, but operates on an already decoded date.
| 
 | Increases the month in a TDateTime value with a given amount. |