advantage of mt instead of ht in h2 unit

[skvishwa]

we have in our unit mt shift reactor as the first reactor for shift conversion while most of the plants - atleast 4 plants i have seen - have ht shift and then lt shift.
is there any benefit of it , because i don't see much of the benefit in steam generation.
and as far as cost is concerned these catalysts (cu based) are way too costlier than fe based (i.e. htshift)and these require additional loop for start up and reduction.
regards,
santosh