Flood Solid Stain for Railings

I've gotten a lot of great tips from this site. Live in MA. PT deck and railings. Full sun. Probably around 10 years old but not sure. Just stripped old semi solid, cleaned, and put down armstrong clark rustic brown. Looks great. I want to do the rails in a white or off white. Looks like you suggest Flood as the solid stain of choice. The rails have been stripped and cleaned but there are still some patches of the old semi solid here and there. My plan is to use flood solid. Let me know if you suggest otherwise. I found a deal for around $10 a gallon, pic below, but looks like an older label. My question is - should I buy new from the paint store or go with the deal from the bargain store / old label. Is the formula any different?