customizing numeric format in alerts

An old style ${VolumePercentUsed} variable has a two-digit precision while the new ${N=SwisEntity;M=VolumePercentUsed} - six-digit.

Don't see a "format output" option in alert configuration either.

Not sure why there are two variables for the same value - but assume that the old style will eventually go away, as these old-style variables aren't listed in "select variable" tables.

Is there a way to format the output of those newer-style variables to a two-digit precision, e.g. "15.18%" ?

Thanks!