You are misunderstanding entirely.
Let's say the macerators in in series like so:
Assume all of the macerators have 1 transformer upgrade.
The MFE is outputting 512 EU/t. The transformer steps that down to 128EU/t. Mac1 receives 128EU/t, but it only needs 4, so it sucks 4 EU/t from the cable and lets the remaining 124 EU/t continue down the line. Mac2 grabs another 4 and sends 120 down the line. Mac3 does the same, sending 116 down the line. Mac4 receives 116, consumes 4 and returns the 112 back to the MFE. So even though it's a 128EU/t line, only 16 EU/t is used. Technically, you don't even need the MFE or transformer upgrades, this could all be done with a BatBox, but it allows you to power a good amount of basic machines off of a single line without fancy wiring.
Im a derp I missed that one HV-Transformer block. It totally makes sense now. Thank you