Proper checking of coolant level

[g0tb00st]

Hi all,

I'm new to the boards, but I've been trolling for over the past year.

Before my wife and kids headed out this past weekend for a day trip, I decided to check the coolant on my 2008 4.8i SAV and noticed that the level was way below the "min" mark in the expansion tank (mind you, this was on a cold car). They took the other truck (Cayenne Turbo-S ) and headed off as I fiddled with the X5. I removed the expansion tank cap, started the car, and ran the heat at full blast (following the directions from the BMW Coolant bottle, but I didn't add any coolant) I just wanted to see whether the tank would fill up or not. It did, and the coolant was between the min/max level.

Quick question, is this the proper way to check the coolant level?

Thanks,
Erik