截(jié)至(zhì) means ‘so far’ while 截(jié)止(zhǐ) means ‘deadline’ or ‘closing date’.
The semantic distinction is caused by the difference between the morphemes 至(zhì) and 止(zhǐ), the former means ‘at a certain time’, the latter means ‘end/finish’.
Therefore, you can express the meaning of ‘up to now’ by saying 截(jié)至(zhì)目(mù)前(qián), and express the meaning of ‘deadline’ by saying 截(jié)止(zhǐ)日(rì)期(qī).
