How did you measure the response down to 32 Hz to know that it was flat?

Lets examine the pro's and con's of closed versus bandpass.

Closed - LF limit at fs of speaker in box, HF limit that of the driver itself, or the LP crossover.

Bandpass - LF limit as much as 1 octave below fs of the speaker in the rear box, HF limit no more above fs than the LF limit is below. In other words the bandpass (single ported) has a symmetrical response centered on the dri=vers fs in its rear enclosure.

So, unless the closed box is going to be at a HF limit above that for which the bandpass is capable of, the bandpass wins hands down. But the bandpass losses when one wants a response greater than about 1 1/2 octaves.

As I so often say, there is no single choice in any of this you have to look at the big picture.

In a home theater for the LFE channels (the .1) anything but a bandpass is not the ideal - beccause this is already a band limited channel.