I woud like to substitue a string on a specific position for specific lines

I've got a file and I would like to change a specific string from "TOCHANGE" to "ABCABCAB"

For every line (except 1,2, 3 and the last one) , I need to check between the 9th and the 16th digits.
For the 3rd line, I need to check between the 12th and the 19th digits.
No checks for line 1,3 and the last one.

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example 1:

Code:

line 3 
12345678901TOCHANGE12345
Line 25,.... 
12345678TOCHANGE12345678
123456789TOCHANGE1234567
TOCHANGE1234567890123456

Only the line 3 and 25 need to be amended

So I would like to get

Code:

line 3 
12345678901ABCABCAB12345
Line 25,...
12345678ABCABCAB12345678
123456789TOCHANGE1234567
TOCHANGE1234567890123456

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example 2:

Code:

line 3 
123456789TOCHANGE1234567
Line 25,.... 
12345678TOCHANGE12345678
123456789TOCHANGE1234567
TOCHANGE1234567890123456

Only the line 25 needs to be amended

So I would like to get

Code:

Line 3
123456789TOCHANGE1234567 
Line 25,...
12345678ABCABCAB12345678
123456789TOCHANGE1234567
TOCHANGE1234567890123456

Do you have any idea about how I could do it?

I tried with the sed command but it works on the number of occurence.
I think it could be done via the awk command

Many thanks

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