Discrepancy b/w Classic & RSSP on defaulting Line Type from the Item Type for Non-Catalog Request.

We have a requirement where a custom line type has been created under the "Manage Purchasing Line Types" task.

Whenever a user raises a non-catalog request and selects the Item Type as "Services billed by amount", we want this custom line type to be defaulted automatically.

In the Classic UI, when we created this line type, it used to default automatically whenever the Item Type was set to "Services billed by amount".
Below are the screenshots for this.

Below are the screenshots from RSSP, where the Line Type is defaulting to "Fixed Price Services" when the Item Type is set to