Flak Units

Have a small head scratcher that maybe someone can help me with.
I have been doing research on my Opa's service as part of a Flak crew.
His original unit was 3./Flak.Ers.Abt.26.
He was captured in March of '45 with Flak-Regiment 59.
I have plenty of reference material on Flak-Regiment 59, and recently got a copy of 'German Order of Battle 1944'. The book made a reference that these replacement battalions usually has a parent battalion of the same number.
I had contacted Michael Holmes a few years ago after studying his great Luftwaffe website and asked if he had any info regarding the 26th replacement battalion. Sad to say he could not give me any info, mostly due to the fact that a lot of records were destroyed.
My questions are is anyone familiar with the battalion numbering system?
Would a replacement battalion share the same number as a parent battalion?
I have a copy of Flak-Regiment 59's operational history.
1.12.44 under 19. Flak-Brigade with le.87 (mot.); Stab, 5./le.196 (v); gem.537 (v); 2., 5.-6./le.722 (o) and 4./le.827 (o); 2./le.827 (o); Stab, 1., 2., 4./le.859 (E); 4./le.999 (v); Stab/gem.zbV 12600 (b.mot.)
1945 in Mittelrhein area (Luftgau XIV), and later under 1. Flak-Brigade.
These are the last 2 entries on the unit history. As you can see the battalions listed don't come close as to being a parent unit of Flak.Ers.Abt.26.
Although I do know that my Opa was on a crew in Paris and he was situated on a rooftop (my mom's recollections), I feel as though I have gotten to an ending in my research.
The only thing that I am fairly certain of is that he would have been with a light or mixed battalion due to the fact of his gun being deployed on a roof top. I don't recall ever seeing a heavy gun in that position.
Any help would be appreciated.