Back-to-front suggests a single item that is the wrong way around or has been reversed, like a shirt with the buttons at the back, or holding a map up the wrong way.
Back-to-back suggests two things touching each other, and unlike in back-to-back housing, the orientation doesn't necessarily matter, especially for abstract terms like agreements and arrangements (in this context).
The phrase "back-to-back agreements" appears to have become prevalent in the early 1970s, but the earliest I found is from this 1956 Petroleum Week:
The other customer-supplier has a "back to back" agreement with Commerce.
However, "back-to-back arrangements" is also synonymously, and also has a slightly older meaning. Here's the 1906 Mineral Resources of the United States
The washing apparatus consisted of a trommel for taking out the coarse material, from which the fines went to two tables with back-to-back arrangements fitted with riffles and mats.
And from a 1933 United States Patents Quarterly:
It is, in effect, only supplying two devices from a common battery, and it was common to do that in these back-to-back arrangements and in carbon buttons for the purpose of getting added sensitivity.
This suggests a similar meaning of next to each other rather than a literal rear-to-rear.