I would never tell you to shoot numbers under 50. (There are some cats where this is possible but in general, even those of us who have been around for a while and shoot low would not shoot numbers in the 40s.)
I am, however, disagreeing with your vet. Most vets set "no shoot" numbers much higher than we do here. They do this for several reasons. Most of their clients do not home test. As a result, they can't manage the curve. Also, telling someone to shoot low is a liability for the vet. They are not around 24/7 and some vets are not even accessible any time after hours. We try to school you to shoot low numbers safely. If you look at the subject lines on the Board, you'll see that people are routinely shooting numbers that are lower than 150. For example, Tess' bean, Ann, shot a 68 at AMPS. Marje and I will shoot pretty much any number above 49.
I am indeed saying that skipping shots can result in swings in numbers. The duration for Lantus is typically around 12 hrs. (give or take). As the remnants of the cycle wear off, BG numbers will rise. Sometimes, they will even spike into high ranges. And then you shoot and numbers drop again. So you skip and numbers rise. If you look at
Ella's SS around 4/24, she was skipping shots. It illustrates my point.
You have to take each day and each shot as it comes. On a day like tomorrow when you must leave, get a +11 and post if you are concerned about Ella's numbers.
Also, what is your shot time? It looks like you stalled your AM shot until 10:30 yesterday. You can adjust shot time by 15 min. at each shot or by 30 min. once a day. An early shot acts like a dose increase and a late shot acts like a dose reduction.