Terminates employment when clients sign on, against the odds (6)

'terminates employment when clients' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.

'sign on against the odds' is the wordplay.
'sign' becomes 'leo' (star sign).
'on' indicates putting letters inside (as in clothing 'on' a person).
'against' says to put letters next to each other.
'the' becomes 't' (the is pronounced as a 't' sound in some dialects).
'odds' becomes 'sg' (I can't justify this - if you can you should give a lot more credence to this answer).
't' put next to 'sg' is 'tsg'.
'leo' placed around 'tsg' is 'LETSGO'.

Can you help me to learn more?