the shop you bought your bike from???

else, i think it is more or less there especially when you didn't buy your replacement chain from there.,..

different shops might charge differently but there is no set way on how to charge especially when you are asking them to work on more than 1 item...

usually, some shops might have a chart to say how they charge for each type of service.. but when you combine a few items, they might charge in one lump sump instead of combining all the items as it would result in too high a cost...

yours is time to replace... already reaching the casing..

better now before it is too late..

most likely to be just co-incidence... but if you have the scientific spirit... you can mount up your 23mm or 25mm with higher pressure and ram the same pothole again to see if it pinch flats?

it is usual to run 25 with lower pressure as studies indicate that at maximum pressure, it is actually increasing the rolling resistance... if my memory serves me right...