McDonald's launched its all-day breakfast menu in late 2015, which finally meant you could enjoy an Egg McMuffin any time your little heart desired. There was one big problem, though: not everyone actually had access to the full breakfast menu all day.Depending on where you live, your local Mickey D's may have the McMuffin or the Biscuit sandwich, but not both. You may be able to have pancakes or oatmeal or sausage burritos, but after 10:30 a.m., you may be denied a McGriddle or an order of hash browns.But don't fret, the fast food chain thinks it has a solution for many of the breakfast lovers out there.According to Eater , McDonald's is considering permanently adding the McGriddle and Biscuit sandwiches to its all-day breakfast lineup. Right now, it's testing the idea in 72 locations in Tulsa, OK.Some may wonder what took McDonald's so long to give this a try. The truth? Grill space. The McGriddle uses up a whole lot of it with its components of hotcake buns, eggs, and bacon or sausage — or scrapple and Spam, if you live in Philadelphia or Hawaii. Not to mention, McGriddles and the Biscuit sandwich need to be heated in the oven, taking precious space away from all the lunchtime items on the menu.No word yet on when or if McDonald's will expand the McGriddle testing to other states before making a final decision.It's no surprise, however, that the establishment is toying with this change even if it may be a difficult one. Since the addition of all-day breakfast, McDonald's has seen a 5.7% sales increase — the biggest sales jump the company has experienced since 2012.