The work-around to not have to manually enter the invoice allocation info is to click on Make and then Payment. So this solves the issue at hand. However, I am still curious as to why the plus sign appears in my local version and not my ERPNext Cloud version. Btw, you can notice that the same is true about the plus sign for Delivery Note.
I would still be interested in knowing about this since our production version is on ERPNext Cloud and we use the local version to tinker around with customizations possible on the Cloud version or certain implementations we want to accomplish before we role them out and change our SOP.
Any guidance would be greatly appreciated.