I have a question about crossover phase.

I am building the Aethers by Paul C. (Undefinition) and I plan to make some minor changes since my listening position is higher than his. The relative position of the acoustical centers between the tweeter and the midranges will stay the same so no issues there. However the relative distance between the woofer and midranges acoustical centers to the listening position will change a bit.

The woofers acoustical center will now be about 1 13/16" further from the listening position relative to the midranges and tweeters than it was with the original design. By my crude calculation this subtracts about 13 degrees of phase from the woofer at the crossover frequency. Am I calculating this correctly and judging by the graph at the link below will it have a noticeable effect on the response?

Thanks,

Jason