Your tip is: "tanto como after a verb never changes.". But your A 2 is "lleva tantas maletas como ...". So "tanto como" changes to "tanta como".

Hola Kong Yiu Louis,

The unchangeable "tanto como" is referring to "as much as" when we are not comparing "things" but we are saying that someone "does something" as much as someone else. 

So, in this lesson there are two parts:

1. verb + tanto/-a/-os/-as + noun + como    (here tanto changes to agree with the noun)

2. verb + tanto como (here tanto como does not change)

I will add a clarification to the tip so it is clear it refers to number 2 cases. 

Gracias y un saludo

Inma