The Austrian arrived last summer from Wigan Athletic.
Downing told the Birmingham Mail: "There has been a flexibility with Scharner playing centre-back and in midfield.
"I think the new manager sees Scharner as a foil with Mulumbu to provide that solidity. They have both done very well together in the three or four games they have played together.
"And here is a massive focus to Paul's game. He does extra training and extra bits. His professionalism is noticeable.
"He's always one of the first in, does extra work in the gym and out on the field.
"He certainly has a purpose to his football, even at his age he has that drive to try and get better."