Hi, yary, thanks for joining us.  Welcome to English Forums.

In this context, it means a special rule applies from the beginning of the deal, and continues to apply up through the specified date.  After that date, the rule no longer applies.

The rule is that if you decide to pay the loan off earlier than originally planned, there's an extra charge.  It's like an early termination of contract charge on your cell phone.

If you're asking whether you have to pay the special charge if you pay the loan off  exactly on 31/10/2008, that's a grey area.  (That would be kinda cold.)  Read the fine print. For example, if I don't pay my car insurance premium by 12:01 AM on the day it's due, I have no insurance.  They don't give me all day to pay.

You might find wording such as "up to and including 31/10/2008."

Best wishes,    -  A.

Sorry about that.  If we go by the dictionary definition, when the calendar shifts from "30" to "31" (the stroke of midnight) you may execute your "early repayment" without fear of being charged the penalty fee.  But October 31 being the last day of the month, you've gotta wonder if that's what they really mean.

And attorneys don't respect dictionaries.  They respect only "precedent."  Once a judge rules on a case, that will be the law, until someone takes the issue to a higher court and wins.

That is, if a litigant can quote case law (a previous case in which a judge ruled that the client had to pay the penalty fee on the 31st, or something with the same principle) the judge is obliged to honor that previous decision.  His ruling may then be appealed to a higher court.  (At least, that's the way I understand it. Other opinions are encouraged.)

Sometimes even the dictionary leaves you scratching your head.

The movie will be blacked out in Boston until 31/10/2008.

The movie cannot be shown in Boston until 31/10/2008.

That is, the ambiguity may rest with the verb, not with the preposition.

Sometimes "through 31/10/2008" can clear it up.