I thought it had to do with the fact that she was away when it happened. Perhaps she's convinced herself that if she had been there she could have rescued him and prevented the death. Her having such delusions of grandeur would not shock me.
Some weeks ago I was thinking it was a part of the phraseology of suicide prevention of "one more day" and reinforced in her new bumper "What a Difference a Day Makes" or even in Wilson Phillips "Hold on (For One More Day)" Since then, I think it is more literal and timed to an actual event and obfuscated and reinforced in her own mind through this metaphorical truth.
I actually don't think she lies left and right, but her perceptual filters however skewed, anger, desparation and just plain stubborness are driving the ship. (ie. she knows now Dynamo didn't make the call and has basically admitted as such, but refuses to apologize out of spite.)
There is a really deep seated anger like a block of coal in her psyche in her over something and this was in place long before she came to Bellgab.