Maximum Ethercat Lenght Cable

Hello,

A customer has a question regarding the maximum cable lenght that can connect between the ctrlX Core and the last Ethercat slave,

I have seen in this post that the XB-EC-12 can accept 100 m max but I do not know if this value is the maximum of all the elements,

https://community.boschrexroth.com/ctrlx-i-o-1lgjjr0v/post/maximun-ethernet-cable-length-for-ctrlx-io-SEwi4gU7wG3KKht

For example, imagine that I have a ctrlX Core and 2 XB-EC-12 bus couplers, can I connect a 100 m cable between the ctrlX Core and the first bus coupler and another 100 m cable between the first bus coupler and the second or the sum of all the cables needs to be 100 m?

Thanks in advance,