Problem text:
$400 and later 210, then one sentence later a formula (amount)*s^2$.
Try escaping like
\$400 and later \$210, then one sentence later a formula $(amount)*s^2$.
so it becomes
$400 and later $210, then one sentence later a formula (amount)*s^2.
Looks like our heuristic works, but the formula at the same paragraph is too much for it to handle.