Problems with [if] and [total-cost]

["Reuven M. Lerner" <reuven@lerner.co.il>]

Israeli credit cards allow customers to pay in installments
("tashlumim") if the price of an item is over a certain amount.  If
the price is more than 150 shekels, they can choose whether to pay in
1 or 2 installments, and if the price is more than 250 shekels, they
use up to three installments.

I have been trying to get a simple if-then statement to work, based on
the current total cost.  I figured out how to get a numeric version of
the total cost, [total-cost noformat=1], but for some reason I can't
get the [if] to work correctly.

I want to do something like this:

    <input type="radio" name="tashlumim" value="1" checked> 1

    [if value 150 < [total-cost noformat=1]]
    <input type="radio" name="tashlumim" value="2"> 2
    [/if]

    [if value 250 < [total-cost noformat=1]]
    <input type="radio" name="tashlumim" value="3"> 3
    [/if]

I've tried lots of different variations on the above, and none seems
to work.  I know that it must be possible, but what am I doing wrong?

Thanks for any and all help!

Reuven