Each month that you are in Builders Club your loyalty factor will increase. If your Builders Club expires then the loyalty factor resets to zero - so don't quit!
The loyalty bonus is a percentage of your daily stipend - it's not a fixed amount.
Example of someone who has 1.5x bonus:
BC - 15 stipend + 23 bonus per day
TBC - 35 stipend + 53 bonus per day
OBC - 60 stipend + 90 bonus per day
You just multiply the stipend times the x to find out how big the bonus is. The bigger the stipend, the bigger the bonus. I've been building a bunch of adventures on <a href="http://www.roblox.com/User.aspx?ID=16537896&userid=16537896&rbx_source=ambassador&rbx_medium=Direct&rbx_campaign=ambpro">roblox</a>