Description of the Bug
Tank size does not affect its capacity.

Screenshots & Video
Tank height 4
https://imgur.com/Gas67Df
Tank height 5
https://imgur.com/R1omlHZ

Logs & Environment
Mod list
AutoRegLib-1.3-24.jar
Baubles-1.12-1.5.2.jar
bdlib-1.14.3.12-mc1.12.2.jar
binnie-mods-1.12.2-2.5.1.186.jar
BiomesOPlenty-1.12.2-7.0.1.2424-universal.jar
buildcraft-7.99.19.jar
Chisel-MC1.12.2-0.2.1.35.jar
CodeChickenLib-1.12.2-3.2.2.353-universal.jar
CoFHCore-1.12.2-4.6.1.22-universal.jar
CoFHWorld-1.12.2-1.3.0.6-universal.jar
CTM-MC1.12.2-0.3.3.22.jar
dungeonmobs-5.7.0-MC1.12.2.jar
DynamicTrees-1.12.2-0.9.2.jar
DynamicTreesBOP-1.12.2-1.4.1e.jar
energyconverters_1.12.2-1.2.0.10.jar
files.txt
forestry_1.12.2-5.8.2.380.jar
Forgelin-1.8.2.jar
gendustry-1.6.5.8-mc1.12.2.jar
Hwyla-1.8.26-B41_1.12.2.jar
industrialforegoing-1.12.2-1.12.4-228.jar
jeibees-0.9.0.5-mc1.12.2.jar
jei_1.12.2-4.13.1.225.jar
JustEnoughResources-1.12.2-0.8.10.50.jar
list.txt
lista.txt
OptiFine_1.12.2_HD_U_E3.jar
Quark-r1.5-138.jar
railcraft-12.0.0-beta-4.jar
RedstoneFlux-1.12-2.1.0.6-universal.jar
tesla-core-lib-1.12.2-1.0.15.jar
ThermalCultivation-1.12.2-0.3.1.8-universal.jar
ThermalDynamics-1.12.2-2.5.3.16-universal.jar
ThermalExpansion-1.12.2-5.5.2.39-universal.jar
ThermalFoundation-1.12.2-2.6.1.22-universal.jar
ThermalInnovation-1.12.2-0.3.1.8-universal.jar

bug has been reported already. it is just that the capacity shown in gui is totally wrong.

Will it be fixed?

yes. this is to send tank capacity info correctly to the client. however, my computer is broken so you have to wait a bit.