The problem with the 0.25 unit dose is that he went too low for safety - 32 mg/dL - and could have had a hypoglycemic attack, which can be fatal.
About the only work around to be able to go back to 0.25 units would be to deliberately increase the carb level slightly.
Also, with Lantus and Levemir, shooting early is like a dose increase and shooting late is like a dose decrease because the amount of overlap increases and decreases respectively. Because of this, we usually adjust times by either 15 minutes per shot, or by 30 minutes once a day.