I'd really like to know, too.
My guess is they didn't know when the hardware was pre-ordered, whether they could get approval for circular.
Which I assume would have been their preference (?)
And why would I think that (other than circular is uncritical on skew)?
(With a multi-LNB dish, skew really just aligns the feedhorns with the satellites.) -

Well, somehow they got authorization to run circular on 118°, right next door to 119° !
Only way the LNBF can distinguish between the two birds is, the LO for 119° is 11250, and the LO for 118° is 10750! -

Plus, I'm also guessing that processing -both- circular and linear through the one LNB would have been a major plumbing nightmare!