Has anyone used Intercompany before in Netsuite, I'm trying to create Intercompany Sales Order but not the preferred one, which is the best approach here? Netsuite is wanting me to change the preffered one.

first you must create IC PO, then all other transactions - IC SO, IC Invoice, IC VB, etc. - will be created from it

It seems in suite awnser it's only using the Preferred Sales order. Preferred Sales Order Form: Set Allow Cross-Subsidiary Fulfillment to unchecked by default (Suite ID: 72354).