I still feel that the terminology is a translation difficulty, and do not accept that using "series" rather than "block" or "batch" is necessarily any improvement, but let's move on to the aircraft side.
I am not insisting on anything - if "block" is more appropriate for Russian "seriya" (note that it is singular), we should start using "block" for LaGG-3, Pe-2 or SB Series too.
At first sight the size of each Series appears low, considering that over 3000 examples were built discounting the later Irkutsk builds. By this listing, no more than 780 had been built by June 1945. Gunston (Tupolev aircraft) states that the main production was on two lines, GAZ 166 and 156 (starting slightly later).
My mistake - Zavod No 23 must have increased Series size from 20 to 50 in late 1944 or early 1945. Gunston was also wrong, there was no parallel production in two factories during the war. Main wartime production was in Moscow Factory 23. Production from 1942 to 1945 was as follows:
Zavod 166 Omsk1942 - 79 planes
1943 - 1 plane
Zavod 23 Moscow 1943 - 16 planes
1944 - 378 planes
1945 - 742 planes
After the war in 1946 - 1949, production was reinstated in Omsk with about 200 planes produced. For Omsk, those postwar Tu-2s were series 8 to Series 18...
Zavod 39 in Irkutsk made further 200 or so planes between 1947 and 1950. Balance to 2500 was made in postwar years by Zavod 23 in Moscow.