Which line was really longer?

The Lake Shore Michigan Southern main line between Buffalo and Chicago was always considered to be less distance than the Michigan Central main line connecting those two points. For many years the NYC public timetable showed a difference of about 10 miles between the two lines favoring the Lake Shore line as the shorter route. The distance shown is 525 miles via Cleveland and Toledo on the LSMS. While the distance given is 535 miles via Detroit on the MCRR main, not including trains crossing the east border at Niagara Falls. Most trains moved on the East Canada Division main using the Fort Erie Division between Welland and Ft. Erie. The CN/GT International Bridgewas used for crossing the border between Ft Erie, Black Rock and Bufflao. In the NYC public timetable, the distance between Ft. Erie and Black Rock is shown as 16.6 miles. A long standing mistake, to be sure. One can stand at either end of the International Bridge and easily see the other side which is not quite a mile away. The Canada Division employee timetables show the distance between Black Rock and Ft. Erie to be a more realistic 0.87 miles. That being the case and other published mileage mistakes notwithstanding, the MCRR main line would have connected Buffalo and Chicago with somewhat less distance than the LSMS line. Depending on whether the information is taken from the ptt or ett, the total distance would have been between 519 and 522 miles. That includes distance discrepancies between Buffalo Central Terminal and Black Rock which occurred between those timeables.
It is difficult to understand why the NYC would have shown, in the ptt, the distance between Ft. Erie and Black Rock to be 16.6 miles without correcting such a mistake.
Would anyone care to offer an educated thought as to why such errors occurred and were never corrected?