I always felt the JWs differ just for the sake of being different in this and other things they teach.
This is the key to most of the practices introduced by Rutherford and Knorr. To be completely different from nominal Christianity, even if there is no basis for it.
As was mentioned, this awesome post was made 12 years ago.
https://www.jehovahs-witness.com/topic/92381/facts-on-crucifixion-stauros-torture-stake
JWfacts has good pages on the cross, especially the reference to the "ellipses" trick when "quoting" from the Imperial Bible Dictionary, which was used in the Reasoning book. https://www.jwfacts.com/watchtower/misquotes-deception-lies.php#Cross
Despite the Imperial Bible Dictionary being available for all to view in Google books, WT again pulled off the ellipses trick in the 2011 Watchtower.
https://wol.jw.org/en/wol/d/r1/lp-e/2011170?q=imperial+bible+dictionary&p=sen
Maybe they are going to ease off of this one.