I was looking into buying a fluid head tripod and was looking at the 525MVB legs with the 503HDV head. It was about $930 on b&h. Then I found the 516 head with 515MVB legs for only $999. Why would a tripod with a 516 head only be $70 more than one with a 503 head? The 525 legs and the 515 legs look identical in the picture, but are the 525 legs A LOT better than the 515 legs?