... the ~ ... is only present if the values are 0.00.

Since you seem to want to capture only a  ~ (tilde), if present, and no other character (including, in one case, a  - (negative sign) in the example below), I would use:

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my $text =
   'foo ~0.00 bar 1.0 fee 0.2 baz 0.03 boff -0.09 zot 10.09';
 my @lag_util = $text =~ m{ ~? \d+ [.] \d+ }xmsg;
 dd \@lag_util;
"
["~0.00", "1.0", "0.2", "0.03", "0.09", "10.09"]
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