Relevant Products: Exclaimer Cloud - Signatures for Office 365 | Exclaimer Cloud - Signatures for G-Suite | G-Suite Light | Signature Manager Exchange Edition | Signature Manager Outlook Edition | Signature Manager Office 365 Edition | Mail Disclaimers
You are creating your signature template and are choosing the font size to be used within your signature template.
You set a value of 13 which you believe to be in Points (PT) but when testing and you review the email, you see the font size has been set to 10PT's instead.
The most likely cause of this issue to occur is because the font size value would have been set at a pixel value.
Ensure that the value you are setting is exactly as required and double check that the value is set to PT rather than PX
Alternatively, you can set the value is PX value instead. See the below guide for a Point to Pixel conversion chart.