formula error ?

[Hobb3s]

It seems there's a calculation error somewhere in the cost estimator. For example:
Octoprint give me an approximate total print time of 10 hrs. (which is accurate, having already printed this previously)

I've set the cost per hour to $1.50 and filled out the other fields with cost of the spool and the density of the material. Now basic math indicates that at 1.50 per hour x10 would be $15, plus the cost of the material. However the cost calculator is estimating 13.74 for the 10 hour print job, including the filament. I tried changing it to 2$/hr and it calculates 17.37$, same issue. Even at 100/hr, it gives an estimate of 729.76.

This makes me think that perhaps the calculator is doing it's own time calculation for the print job and is off the mark by about 25-30%.

[tophattwaffle]

Also noticing a issue with the calculated price. Have my price for material set to 0, and price per hour to 2. Did a 2.5 hour print and am being told 10.78. Expected it to be around 5.