The primary “drawback” of bypass valves located at the “closed” end of the filter involves the oil flow path. Oil “bypassing” a filter with the bypass valve on the “closed” end of the filter must pass along the entire length of the filter media (which likely contains trapped dirt) before reaching the bypass valve. As the oil passes along the “dirty” element, it’s possible for some of the dirt to be swept into the oil passing by, and through the bypass valve and into the oil passages.
If the bypass valve is located at the “open” end of the filter, bypassing oil goes directly from inlet to outlet and doesn’t pass over the “dirty” filter media. How much of an advantage this may be is probably debatable. If the media is clean, or effectively traps and holds any dirt, oil passing by will not pick up any dirt.
There is nothing wrong with using the "closed end bypass" filters you already have. If you are concerned with, or want to minimize the effects of bypass valve location, you might consider using the filters with bypass valves on the "closed" end during times of the year when bypassing is less likely (during the warm months when the oil is generally warm and can pass more easily through the media).
