Why is Loewen pronounced "Low-en" and Toews pronounced "Taves"?

Of all the mysteries that have befallen the Mennonite community over the centuries, the most baffling is why Loewen is pronounced “Low-en” and Toews is pronounced “Taves.” For consistency they should either be pronounced Layven and Taves or Lowen and Toes. Now some will point out, “ahh, but I do know some strange Loewen family out in Chilliwack or someplace who pronounces it Layven,” or “I did meet a guy once who pronounced his name Toes.” Sure, okay, but we can’t use the outlier to prove the rule. The question remains, in a community, for example Steinbach, where all the Loewens and Toewses immigrated from the same colony in Ukraine, spoke the same language, and have lived together in blissful harmony for more than century and a half, why would they be inconsistent in their pronunciations