A tilting level was used to run precise levels to a construction project benchmark from benchmark DAM, which had an elevation of 345.901m. The line was run along a road that goes up a steep incline. To expedite the job, backsight distances were kept to 50m while foresight distances were 25m. The total length of differential levels was 5248m. The measured elevation difference was 21.051m. What is the corrected project benchmark's elevation if the instrument had a sight line that declines at a rate of 0.5mm per 50m?