You don't need the recovering seed when using newest version of electrum + trezor. Only the PIN.
I don't think this is an accurate statement.
Even if you can import the recovery seed, it doesn't mean you need to.
It is commonly considered more secure to keep the keys in the TREZOR and use Electrum/Mycelium/etc. as an interface to the TREZOR. This way Electrum acts as a replacement for the myTrezor web interface.
See
http://doc.satoshilabs.com/trezor-apps/electrum.html .