If you have a cycle that starts as a bounce is clearing you could very well see a drop from red to green in 3 hours. Remember, Lantus is slow acting. The highs of a bounce are the result of the counter regulatory system dumping hormones that raise BG. How much will be dumped and how long their effects will continue is unknown. At the same time, underneath all that, your Lantus dose is doing its usual slow and steady thing although it does not appear that way due to the bounce. When the counter regulatory system has raised the BG back up to a level it feels is safe it simmers down and stops (until the next time) We can't know how high a bounce will go, or how long it may last or for that matter even if there will be another in the future. These are unknown variables. Should the end of a bounce coincide with Lantus onset the effect can be a dramatic drop in BG. The moral of this story is you must consider the role the end of a bounce may have played in any steep drop in BG. Fast and steep is simply not the Lantus method of operating. Basing dose decisions on the nadir values is what keeps you safely steady on the path to regulation.
Draw some coffee or tea or water with food coloring into a syringe to your 1.25 and keep it to use as a guide to compare against when you draw your shot and call it 1.25. Consistency is key.
please point out the dates from your spreadsheet that you see this pattern.
Always consider the role clearing a bounce plays is a dramatic drop and remember that dosing with Lantus is based on nadir values