The price of $AIV can be highly volatile, as in any market. When you made a trade yesterday, you did so based on the information and prices available at that time. Market conditions are highly volatile, and sometimes prices rise or fall unexpectedly.
Calculating the $Dinar - $AIV fund is quite simple. The solution is as follows: take the amount of $Dinar you have, divide it by the total $Dinar in the fund, then multiply that result by 200,000 (that's the daily AIV limit), and finally, multiply it by 0.97 (since there's a 3% fee).