Calculating total from number of minutes and cost p/m

I need to calculate the total cost of outbound calls based on the total duration of outbound calls multiplied by cost per minute.

For example, in a given month, the total duration of outbound calls is 261:16:34 being 216 hours, 16 minutes and 34 seconds. I have this figure in cell A1 with the format [h]:mm:ss.

I then convert this to minutes in cell B1 by saying B1=A1, but having the format [m], which gives me 15676.

In cell C1, I have the cost per minte value of £0.026. But when I apply the formula D1=B1*C1, I get £0.283, when 15676*£0.026 should in fact be £407.58.

Any ideas?

No need for B1 as I see it

D1: =INT(A1*1440)*C1