It is easy to be misled by a seat post tube that terminates quite a ways above the top tube/rear stays junction. That bit of seat post tubing above that junction has much less strength to resist the backwards forces that the seatpost puts on it. Everyone is giving you good advice, be sure the seatpost goes below that junction by several inches. I have seen several bike frames broken at this junction by the seatpost forces. I am not a fan of the downward sloping top tube for heavier riders. It can put so much seatpost out from the top tube/seat stay junction that it acts like a big pry bar on that area of the frame. Mountain bike frames are the exception. A high top tube is unsafe for MTB riding.