LNKEDT 64-bit mode assembler in AMODE 31

[Brite]

We have some assembler programs written in 64-bit mode (using 64-bit mode 
instructions) since they allocate storage above 2G line to put some tables. But 
we still link-edit them with AMODE 31. Is this OK? When we test that, it's very 
slow. Any concern besides the performance issue?