I just purchased the same machine (under the "Sieg" brand, from Chronos in the UK), and found myself asking the same question.
This was the first post I found on the subject. However, I subsequently found the answer in the PDF instructions on the Micro-Mark site, so I thought I should share it with you. It's actually not very interesting at all, but here goes. This is what the manual says....
"Use T-block (38) as a gauge to set the bending blades into the ram. The smaller blades, when used in
combination, will then be located at the same height when installed. Place the T-block upside down in
the prism channel and lower the ram with loosened blades onto it. Then secure screws for alignment."
So, in short: "it saves using your fingers to set the bending blades up" Yawn!
Sorry it's taken 3 1/2 years to improve on A-Team's answer - I expect 3v0 probably lost his T-block by now ;-)