SP 21 - asynchronous

I am new to the list. We are looking to go to SP21 but we are wondering how much of an issue this asynchronization will be for our customer service. They multitask while they are waiting for the orders to process and they also enter multiple lines on one sales order, moving from line to the next and with SP21, I believe they will not be able to do this until the entire row is done processing. Has anyone moved to SP21 and experienced a slow down with the processing time of an order?

AS/400(Model - 720 / 207F Porcesssing Feature Code) XE Update 1 SP19.1F Thin Client(Citrix) Fat Client

Sales Order Entry (as designed by JDE) is asynchronous. This mean that you are able to enter the next line number while the previous line number processes. Unless you modified this it should operate the same on SP21.