A lot of oven temperatures are inaccurate.  For years I've used just an inexpensive stainless steel instant-read oven thermometer to remedy this issue.  Oven temperatures vary so the amount of time your muffins need will vary also.   Use the toothpick test to test your whole wheat vegan muffins.  If the toothpick comes out clean, then the pumpkin peanut butter muffins are done.  If the toothpick comes out with batter, bake the muffins for 1-2 more minutes and check again.