3566111 - Unable to create Base and Alternative units of measure with Dimension TIME in Product Master

• Alternative Units of Measure are calculated incorrectly when using a Unit of Measure with Dimension time
• Not possible to maintained UOM conversion 1 Year = 12 Months in the Product Master

• SAP S/4HANA Cloud Public Edition
• Master Data

1. Access the Change Material app 
2. Input a Material with Base Unit of Measure Month 
3. Access Additional Data tab and Tab "Units of Measure"
4. Maintain X = 1 YR ( AUn)
5. Press Enter
6. Message ' Alternative units of measure have been checked and corrected' appears and conversion is showing 6    YR    Year    <=>    73    MON    Months instead of 1   YR    Year    <=>    12    MON    Months

System works as designed

The unit conversions are performed based on the conversion factors with respect to the main (SI) unit of the dimension.

For the dimension TIME, this is the second. Every unit within this dimension has a conversion factor that is based on seconds.

Examples: 1 minute = 60 SEC, 1 hour = 3600 SEC , etc

The units minute, hour, day, week can be determined easily because they are unique.

However, defining the values for month and year is not so obvious:

1 year could be defined as 365 days or as 366 days or as 365.2778 days because the concrete value might vary.

Similarly, 1 month could be defined as 30 days or 30.4398 days because it can be 28, 29, 30 or 31.

There has to be a defined value that is taken for each conversion and as seen above, you can either take a year always as 365 days and a month always 30 days, but then 1 year = 12.1667 month

or you can take 1 year as 12 months, but then you will lose one of the previous fixed conversion factor, i.e. either a year is not 365 days or a month is not 30 days.

In SAP standard, the decision was to take the above settings: 1 year = 365 days and 1 month = 30 days.

We don't recommend to change the conversion data, but if it's absolutely necessary for your business requirements you might create your own custom unit of measure in the configuration activity Check Units of Measure (Configuration Activity 102179)  with custom Unit value for month and year so that you get the factor for year = 12 month for the factor for month.

example:
ZYR: numerator = 31560000, denominator = 1
ZMO: numerator = 2630000, denominator = 1

Please note that changing the conversion factors of the standard units of measure like Month , Year will affect all other areas as well, the maintenance is not application specific.

Check Units of Measure (Configuration Activity 102179) , SI Unit , DIMENSION , "Manage Product Master Data" , KBA , LO-MD-MM , Material Master , How To