The NYXLs are slightly lower tension than the normal nickels.
My usual XL165 strings are - 42.52, 48.35, 45.34, 38.08 (G,D,A,E)
The equivalent NYXLs are - 40.28, 47.06, 44.58, 36.96
At this time of year I am not surprised at the rate that your strings are dying - we've played some really hot gigs and almost had a set go on me after 1 pretty short gig but putting it into perspective, I bought 8 sets in December 2016 and I am on set number 7 now. That is using the same bass for rehearsals and wedding/function gigs.