[plt-scheme] nonstandard installation

We have a heterogenous network of mostly Solaris servers for 
undergraduate computing. Our sysadmins use a locally-brewed software 
distribution system which involves building on one machine and pushing 
files to other machines. Thus their installation of PLT Scheme will not 
run setup-plt on a destination machine (except the build machine).

I asked a tutor to build a copy of PLT Scheme from scratch in their 
local account, and in running a trivial program, the "user time" of the 
local mzscheme is twice as fast as the officially-installed version.

What might cause this problem, and what can I suggest to the sysadmins 
to fix it that might be consistent with the way they do things? Thanks. --PR