I'm usually pretty wordy, but let me keep it terse for a change:
1).
Do not mix subscription problems or hardware with FTA.
That's the very best solution for a whole laundry list of reasons. - :up
2).
Ya can't get circular Ku DBS frequencies through a BSC-621, a
CK-1, nor BUD LNBs on a Chaparral feedhorn (nor similar).
Remember please, the LO is wrong.
3). using a spare DBS LNBf mounted beside your existing BUD LNB hardware is a possibility.
But it's also a poor solution.
See #1). above. -