I actually share your users feeling too " its time consuming to update both scheduling agreement and the info record."
But maybe training could help to make him understand that an info record must not necessarily have the same price as a schedule agreement.
Info record price is a general price that applies if no special agreement (such as contract and schedule agreement) exists
Since you usually have high volumes in agreements you get special prices. If you order without that reference then your order does not fall under that agreement and you may have to pay a different price. From this point of view is updating the info record with the agreement price not the right approach.
And there is no option via customizing to do such updates automatically, it is even clearly explained in an OSS note that the info record price is never updated automatically from a purchasing document