Outlook 2011 For Mac | Formatting Issue

Hi All,

I am using mac pro with OS X version 10.9.2 and Outlook 2011 version 14.3.9.

I am having a few issues with the fonts while using outlook:

1. I have created a default signature using Calibri font with size as 16. This is the default signature to be applied for all emails (new & replies). I use HTML format for all my emails. However I noticed that when a new email is drafted, all goes well and the signature looks good. However while replying to emails, I noticed for some emails the font changes to Times New Roman automatically and for some the Font Size Changes (font still remains as Calibri). I tried setting the default font, signature etc; but no luck. Any idea what could be the problem and how can I fix this?
   
2. When sending an email from Mac, the users having a windows environment receive my email with different font sizes and formatting. Any idea what could be the problem and how can I fix this?
   
   Thanks in advance.

Sethu