Power and BTU ratings calculation

Hello all,

Hopefully someone can help with my confusion. I am trying to calculate the power requirements and BTUs between two servers that are identical with everything but the storage devices.

I am building two servers, where the chassis power supply specifications are:
1000W Output @ 100-140V, 12-8A, 50-60Hz
1280W Output @ 180-240V, 8-6A, 50-60Hz

All the additional components (motherboard, cpu, memory, etc) will come from different manufacturers but will be the same in both servers.

The main difference between the two servers will be:
Server 1: 12 x 4TB traditional 3.5" hard drives
Server 2: 12 x 2TB SSD drives

The confusion I am having is that I would expect that the power requirements to run Server 1 would be significantly higher than Server 2 because traditional hard drives require significantly power power (at startup and normal operation). Solid state drives require a lot less power. However, the manufacturer is telling me that the power ratings are the same because the power supply dictates how much power is used.

So, assuming that the manufacturer is correct on the power requirements. What about the BTUs? This is definitely going to be a very different value. The problem is that BTUs are usually calculated with voltage and current.

Any advice is appreciate.

Thank you,
Doug