The phrase "preferably at the same time" is correct and can be used in written English.
It is typically used to indicate that something is preferred to happen simultaneously or at the same time as another event or action. Example: "We encourage our employees to attend the training session, preferably at the same time as their colleagues."
Warfarin is taken every day, preferably at the same time each day, with or without food.
I particularly enjoyed the return of Bree's evil son Andrew from "kid jail", hell-bent on a) getting laid by his overgroomed boyfriend and b) hurting his mother as much as possible, preferably at the same time.
Admittedly, Gordon Brown is also responsible for the whole of government policy, or at least thinks he is, so he should probably appear as well, preferably at the same time as Mr Blair.
Instead, it ends with the tagline: "Be your beautiful self", a goal that can presumably only be achieved by allowing all and sundry to photograph you endlessly, preferably at the same time as you tearfully smother Dove anti-cellulite intensive firming gel into your lumpen cottage cheesy thighs.
You should ideally check your pulse every day, preferably at the same time.
4. Return to this setting, preferably, at the same time to build a habit.
"Preferably meditate at the same time every morning.
I want to speak to all the owners, preferably all at the same time".
Viewers had to be ringside for the main event, especially if it involved an argument or a hot tub or, preferably, both at the same time.
There is a new imperative to look busy in public, to be texting, talking to someone on the phone and to be checking e-mail (preferably all at the same time).
The message is clear: we all need cheering up a bit – so if you wear anything this spring, make sure it's startling pink, fiery orange, or preferably both at the same time.
