Pre-transformation rules do not work for orders created through REST API

Summary

Sales orders created through REST API not using pre-transformation rules, expects OM extension

Content

Why the sales orders created through API not using the out of box pre-transformation rules, instead it requires to have OM extension.   

NOTE: We are using pre-transformation rules to assign the line type and billing transaction type based on the order transaction type. 

Expected : Sales order created through REST api must use the out of box pre-transformation rules, this is more configurable. 

Version

20B