ACL options : SpamAssassin™ reject spam score threshold

Service configuration: Exim configuration manager: ACL options : SpamAssassin" reject spam score threshold (5.5?) This seems to stop the forwarding of spam (when a POP3 account is also enabled) However ticking this disables spambox and all spam is automatically deleted (it doesnt even show up in the Mail delivery reports) and spam box cannot be checked for legitimate mail. Is that correct? Does it work like that?