Setting contact's email format in Outlook 10 does "stick"

[rrr100]

I want to set the email format for one contact to "plain text".

So I followed these instructions:

"Method 3: Change the specific contact format


The sender can use the following steps to set plain text in the recipient's contact record:
1) Open the recipient's record in the Contacts folder.
2) Double-click the recipient's e-mail address.
3) In the E-Mail Properties dialog box, click Send Plain Text only under Internet Format."

But after doing this, when I create a new email, then add this person's address, it still says "Let Outlook decide best format", not "plain text".

Why doesn't the contact's info apply in the new email?

thanks