Oh yea I'm sure cutting a bunch of holes in it and then propping one end up and having it support itself plus the weight of all the building materials you added at an angle so it concentrates all of the force onto one short edge plus the unsupported span of the floor will drive that expectancy way up.
20 years with very large portion of it on the sea exposed to the elements and with minimal to no maintenance. That's a very damn important detail
Oh yea I'm sure cutting a bunch of holes in it and then propping one end up and having it support itself plus the weight of all the building materials you added at an angle so it concentrates all of the force onto one short edge plus the unsupported span of the floor will drive that expectancy way up.