Hey Ray, I've just "scanned over" the other posts/replies, the only way the the numbers stack up for your cab is that they are all 75w 8 ohm speakers (x 4) in your cab. so in stereo you can have 2 x 4 ohm or 2 x 16 ohm (2 x 16 ohm is my recommendation given your amp likes 8 or 16 ohm loads). Hey if you had a ADA B200s I'd go for the 4 ohm load...
Understand that:
in parallel 8 + 8 = 4; 16 + 16 = 8, 4 + 4 = 4 etc (halves)
in series 8 + 8 =16, 4 + 4 = 8 etc (doubles)
So many boxes are wired in a combination of series and parallel to give the power amp the best nominal impedance. Your box gives you choices..., Mono 300w (2 ohm or 8 ohm). or stereo 150 w per channel (4 ohms or 16 ohms) because the speakers are 75 w 8 ohm.