That's strange Jeff, I have seen many problems on those axles & never seen the top bushing give any trouble before. No matter how bad the lower ones have been, the top ones are usually so tight, I have to shrink the bushings to change them.
Most times with the lower bore, one half of the hole is near perfect condition. To get guys going fast I have filled the worn areas using a nickel electrode & by just using a burr & grinding stones almost the same size as the bearing, I have been able to reclaim the hole, good enough to tap the bearing cup back into position. When complete, be sure the bottom of the hole gives the bearing a good even support all way round or else it won't last long.
It's not the textbook way to repair (removal & stripping of axle, welding & line boring) but when given the options, owners always choose the "get me going quick" option.
I'm not sure what your hole will look like, but having the half good hole to start with gives you a good guide for bearing position. Using the nickel rods is expensive, but they work a treat with the ductile iron & if it needs to be machined at a later date, they won't crystalize the casting as using normal type rods will do - & risk breaking the housing under load!
BTW - be sure to show the operator/s what a grease gun looks like & tell them to use it often!
