Indeed. you are right.

Quote from Miles and smiles Elite benefits:
"Last Minute Upgrade. You can have your flight class upgraded to Business Class at time of check-in by redeeming miles from your Miles&Smiles account as an Elite member upon presenting your paid Economy Class ticket and your Elite Card at the check-in. In order to receive this service, there must be an available seat in Business Class for the requested flight, and sufficient miles in your membership account . Last minute upgrade service during check-in can be applied for Elite Member and one other passenger who travels together with Elite Card holder on the same flight route by redeeming miles from Elite member’s account. "

And elite plus:

"2 Complimentary Upgrade on any Turkish Airlines flights:
As an Elite Plus card holder, your loyalty will be granted with 2 upgrades within each Elite Plus membership year without redeeming your miles from your account. You may use this privilege on any Turkish Airlines flights you wish, to upgrade your paid Turkish Airlines Economy Class or Comfort Class flight to Business Class. Please keep in mind that the upgrades cannot be used by other persons except the Elite Plus card holder. Upgraded flights will earn paid Economy Class miles.
The validity of the unused free upgrades will not be extended for the next membership year."