You say that you are 'getting measurements' from 1 to 7 C, but don't say how those measurements are being taken, or whether the thermometer being used is accurate or not, or if not accurate, how inaccurate ... even where in the fridge the measurements are being taken will have a huge bearing on the readings you get, along with how often the fridge is opened, how long it is open for ...

Basically, if it keeps stuff cold, then it's working. If stuff starts freezing, then it's working too well (and needs adjusting). If stuff isn't cold, then it needs to work harder (and needs adjusting)

Unless you've got a certified calibrated thermometer in use, then getting into too much precision is pointless.

Bear in mind what the fridge is doing - it is designed to slow the multiplication rate of bacteria.

Virtually all foods will have bacteria on them, to some extent. In small numbers, they're harmless, and the immune system in your body will wipe out the intake quite easily.

However, in large quantities, they can overwhelm an immune system (hence why people with compromised immune systems, which are more easily overwhelmed, have to be very careful with foods).

Bacteria multiply really well - roughly doubling every 20 minutes - at about 33-37 C. Below about 10C, they do really badly though, doubling (roughly, it depends on the species of bacteria) every 12-18 hours.

So having the fridge 'cold' is good enough.

I believe fridges should be between +2C and +5C but I've never seen a specification that states where in the fridge it should be measured - from my own checks it's quite easy to get a 7C spread from top to bottom.

Our home fridge, is adjusted to give +5C where the beers are, just above the salad drawers - our touring caravan has to be adjusted warmer, at +7C to avoid the freezer elements frosting up which warms the fridge up - we've never noticed any difference in food quality or life - it's just the beers are less cold!