That is a big part of Misty's problem. Her story about what they did that day does not make sense. IMO, that story was the normal routine not what actually happened because she never gave "specifics." She started to say what Ron was doing that day then said he laid around until time to go to work while dressed in his work clothes. That told me she did not know what Ron was doing that day. Misty had Jr. playing then taking a nap so she stayed home while Ron picked up Haleigh. Misty forgot that she had said Ron and her slept until noon after dropping Haleigh off at school. Misty forgot all about Jr. IMO, there was never any specifics or details that could be verified because she did not know.
I don't think Misty was there that day. But felt or was told she had to say she was. TN had said at the beginning that Ron and Misty got together on Sunday night, stayed up all night talking and were together all day Monday. If Misty veered from that story then it cast suspicions on TN.
Although I think anyone who takes a LDT is asking for trouble, I also do not think Misty ever had a chance of passing a LDT. At the very least, I would think you would have to believe what you are saying. Then you need to want to take the test, not be stressed out because you were forced to take the test. Misty was pressured into taking them. Tim Miller said one time Ron and another time TN told him after Misty refused to take a test that they would talk her into it. A couple hours later, Misty took the test after writing out that she was going against her attorneys advice because she wanted to help find Haleigh. Of course, Ron did not want to help find Haleigh enough to go against his attorneys advice and take a test.
I've always felt that she was told to never admit she did not know or remember such as what Ron did that day because it would make her look like she was lying. Then Misty was also fed stories, maybe this happened, maybe that happened, and would relate them but did not believe them herself.
IMO, Misty was set up to fail those tests to damage her credibility so if she ever did tell the truth, no one would believe her.