Bridge heights

Seems to be more than enough bridge strikes recently but I’ve noticed a couple of anomalies near where I live.
On the A645 coming from Knottingley to Pontefract there are 3 or 4 warning signs saying there’s a 14’ 9" bridge ahead. But the bridge was changed and I’ve been under with a 16’ 2" trailer. Same deal coming on the A639, couple of warning signs of a 14’ bridge which is actually 15’ something.
So it’s not always cut and dry.
Just saying

On the A428 there’s one between Northampton and Crick which is signed miles away as 14’6" but when yii get there its 14’3"