Difference between 5.3 and 5.7 xlate

Our test interface engine is currently running Cloverleaf 5.7 (our production engine is still 5.3).  When building the test engine, I just copied the xlates (and other files) from the 5.3 server.  I’m seeing something unexpected when trying to create a new xlate on 5.7.

An example: On 5.3, when I select PV1:3 from the Input Message Format box, the text 0(0).PV1.00133 is displayed.  When I make the same selection in 5.7, it displays 0(0).PV1(0).#3(0).  Is this equivilent?

In the xlate, I wanted to concatenate 0(0).PV1.00133.[1] and 0(0).PV1.00133.[2].  In 5.7, are subfields still designated the same way as in 0(0).PV1.#3(0).[1]?

I think I’m going to just scrap this xlate and convert it to a tcl proc instead.  But I’m worried about all my other xlates and any future ones I need to create.