sed - Changing pattern with specific number of digits

i m trying to perform a substitution on the following group of lines :

1AA20160817BBBBBDIGITS1NUMBER1STYLE59        00002200000220
1AA20160817BBBBBDIGITS2NUMBER1STYLE60        00000000000220
1AA20160817DDDDDDIGITS3NUMBER2STYLE60        00000000000486
1AA20160817DDDDDDIGITS4NUMBER2STYLE59        00004860000486
1AA20160817FFFFFDIGITS5NUMBER3STYLE602523111100000000000000
1AA20160817FFFFFDIGITS6NUMBER3STYLE59        00000820000000

I want the final output to be like this :

1AA20160817BBBBBDIGITS1NUMBER1STYLE59        00002200000220
1AA20160817BBBBBDIGITS1NUMBER1STYLE60        00000000000220
1AA20160817DDDDDDIGITS3NUMBER2STYLE60        00000000000486
1AA20160817DDDDDDIGITS3NUMBER2STYLE59        00004860000486
1AA20160817FFFFFDIGITS5NUMBER3STYLE602523111100000000000000
1AA20160817FFFFFDIGITS5NUMBER3STYLE59        00000820000000

The change is one digit, just before "Number" on every second line. The patterns in the style of BBBBB/DDDDD are times, the last character being the seconds indicator.

I want it to check for a specific number of characters and perform the change there, i ve written the sed to do that task and its like :

sed -i.bak "s/^\(.\{1\}\)$scenario$datein\(.\{6\}\)$pod/1$scenario$datein$timein$pod/g" $1

The rest of the code is in Perl. Could one of you help me do the same substitution in Perl? Or perhaps tell me how i can run this sed command, from a perl code? My problem is the files in question are huge, and bash takes too long to read every line, and perform the substitutions. Thanks in advance.