Leon wrote:
2. Does it seem that a flush fit would be harder and require greater
expertise than having a lip?


The very reason I commented with the comment I commented
with, the added cost of labor to sand the two surfaces flush
with each other and not sand through the veneer on the
cabinet bottom, i.e., experienced workman.

UA100, who doesn't have a problem with the lip, just that
"better made" casework doesn't have a lip...