Mage Counterspell

Is mage Counterspell with improved CS a 10 interrupt?

I got locked today and with basic math, assuming he had imp CS 6+4 = 10.

It’s 10 seconds base, 4 second blanket silence 2/2 improved, so you can use it as a blanket or 10 second lockout. It compounds as a 10 second lockout with a 4 second blanket, so if you get interrupted successfully on a flash heal, it’s 10 seconds out of holy and 4 seconds out of every school.

sick thanks!