Paint problem? I am painting the workshop surrounded by my backyard and I...

I am painting the workshop surrounded by my backyard and I am using a latex exterior paint. The top half looks great but the bottom partly where the sun hits it mostly is not covering ably. I am paying $30 a gallon now. My dad recommended a enamel-latex paint that it would cover the matured wood better but it is $50 a gallon. Is this what I should do?
Answers:    You probably should have used a one coat primer prior to fine art. This would have given you a more uniform surface to paint. There are heaps good brand on the flea market. They run from about $10.00 a can to $20.00 for a gallon. Good Luck!
Since you've already purchased the paint, I would simply do additional coats surrounded by what you are already using.