#! perl
use strict;
use warnings;
use Data::Dump;

my $doc =
{
    _source =>
    {
        sheets =>
        {
            sheet1 =>
            {
                Sheet_Name => 'Ex-Sheet',
                formulates =>
                [
                    {
                        0 =>
                        {
                            colName => 'Ex-Col1',
                            formula => '((DelvSts = Deleted + RcdTyp = DelAck) & RcdTyp = DelRecpt)',
                            total   => 'false'
                        },
                    },
                    {
                        1 =>
                        {
                            colName => 'Ex-col2',
                            formula => '((DelvSts = UserIncomingSMBarred & LFR = SMSC_PR_LC_SMSC_Encoding_Error) | RcdTyp = DelRecpt)',
                            total   => 'false'
                        },
                    },
                    {
                        2 =>
                        {
                            colName => 'Ex-Col3',
                            formula => '(RcdTyp = DelAck + OrigInf = SMPP)',
                            total   => 'false' 
                        },
                    },
                ],
            },
        },
    },
};

print "BEFORE:\n";
dd $doc;
print '-' x 30, "\n";

my @new_formulae = qw( abc mno xyz );

for my $sheet (keys %{ $doc->{_source}{sheets} })
{
    for my $columns (@{ $doc->{_source}{sheets}{$sheet}{formulates} })
    {
        for my $one (keys %{ $columns })
        {
#           print $columns->{$one}{formula}, $/;
            $columns->{$one}{formula} = shift @new_formulae;
        }
    }
}

print "AFTER:\n";
dd $doc;
print '-' x 30, "\n";