Maybe something like this will get you started. Try playing with the threshhold and moving average period (see examples):

#! perl -slw
use strict;
use List::Util qw[ sum min max reduce ];

my %cases = (
    A => [ qw[ 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 1
+7 17 17 17 17 17 ] ],
    B => [ qw[ 17 17 17 17 17 17 17 17 17 17 17 17 16 17 17 17 17 17 1
+7 17 17 17 17 17 ] ],
    C => [ qw[ 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 1
+7 17 17 17 17 25 ] ],
    D => [ qw[ 17 20 17 20 17 20 17 20 17 20 17 20 17 20 17 20 17 20 1
+7 20 17 20 17 20 ] ],
    E => [ qw[ 17 20 34 29 36 22 18 25 19 19 19 43 52 37 28 19 17 17 1
+7 20 17 27 36 47 ] ],
    F => [ qw[ 17 20 23 26 29 32 35 38 41 44 47 50 53 56 59 62 65 68 7
+1 74 77 80 83 86 ] ],
    G => [ qw[ 17 20 20 26 25 26 30 34 38 41 44 39 42 46 50 58 52 55 5
+5 55 55 56 59 58 ] ],
);

our $V //= 0;
our $THRESHHOLD //= 1.1;
our $MOVING //= 5;

for my $case ( sort keys %cases ) {
    my $v = $cases{ $case };
    my @moving = map{
        sprintf "%.2f", sum( @{ $v }[ $_ .. $_+$MOVING  ] ) / $MOVING
    } 0 .. $#$v - $MOVING;

    my $min = min @moving;
    my $max = max @moving;
    my $leak = 'no leak';
    if(
        $moving[ 0 ] == $min and $moving[ -1 ] == $max
        and ( $min * $THRESHHOLD ) < $max
    ) {
        $leak = 'a leak ';
    }
    printf "Case $case has %s %s\n", $leak, $V ? "[ @moving ]" : '';
}

__END__
[20:34:52.28] C:\test>junk47 -THRESHHOLD=1.10 -MOVING=5
Case A has no leak
Case B has no leak
Case C has no leak
Case D has no leak
Case E has no leak
Case F has a leak
Case G has a leak

[20:35:07.79] C:\test>junk47 -THRESHHOLD=1.07 -MOVING=5
Case A has no leak
Case B has no leak
Case C has a leak
Case D has no leak
Case E has no leak
Case F has a leak
Case G has a leak

[20:35:16.82] C:\test>junk47 -THRESHHOLD=1.07 -MOVING=15
Case A has no leak
Case B has no leak
Case C has no leak
Case D has no leak
Case E has no leak
Case F has a leak
Case G has a leak

[20:35:25.46] C:\test>junk47 -THRESHHOLD=1.03 -MOVING=15
Case A has no leak
Case B has no leak
Case C has no leak
Case D has no leak
Case E has no leak
Case F has a leak
Case G has a leak

[20:35:32.66] C:\test>junk47 -THRESHHOLD=1.025 -MOVING=15
Case A has no leak
Case B has no leak
Case C has a leak
Case D has no leak
Case E has no leak
Case F has a leak
Case G has a leak
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