Roof window - costs with/without installation

Hi,

we are considering having two additional roof windows installed in the attic, which is still not insulated.

I picked one from the market leader, costing about €440 for a 78x118 pivot window at the local large hardware store.
Plus this flashing frame, making a total of €510.

I have now called 2 craftsmen, both talk about approximately "€1200 net" or "around €1500" for delivery + installation.

I would have assumed that installing a roof window can take 4 hours? Hourly rate €60? That brings me to around €750.

Where is my mistake? Did I forget something?

Best regards
Simon

DIY store goods are reluctantly installed. Also, profit is made on the purchase. It’s like with my car repair shop. If I buy new tires online, installation costs 40€ per wheel. If he orders from his dealer, then 25€.

Did I forget something?

- Profit/Loss
- Ordering, coordinating, checking the installation site also costs money
- "Non-productive" employees also have to be paid
- The order situation in the construction industry

Also the question if it really was done in 4 hours. Does the roof have to be uncovered and covered again? Do rafters and beams need to be supplemented? (I assume so). All that takes a lot of time.
Depending on the scope of work, the price is okay.
Just windows, without having to do anything else, installation should be around 1000-1300€.

DIY store goods-->Goods from the market leader. Therefore, I assume they get even lower prices. Or do they all calculate with the MSRP prices?

Profit, overhead costs, order I would now include in the hourly rate, is 60€ as an assumption too low?

The roof does not need to be covered, only an opening created. One person said that would be about 120€.
No rafters or beams will be added, windows fit in between.

1000€ would still be within the fluctuation range of my rough calculation.

A elux installed here in 2017 cost 850 plus tax, so a good 1000 in total. Even if the trade is that small, it brings in more than just work....that's why the window doesn't end up on the invoice for 510, but for 810, bet?