We did not get an update on what floor Luffy and co are on this chapter. This implies to me Oda is timing Luffy's arrival to the top to chapter 1000.
In 993, we started with Luffy on basement floor 1.
Followed by the first floor in 994.
However, Oda halted the update this chapter. All we got was Luffy and co heading forward, floor unspecified. I'll take that to mean the trio is still on floor 1, and I see why Oda did that.
Had we followed the trend set on 993, Luffy would've reached the top on 999.
993 - B1
994 - F1
995 - F2
996 - F3
997 - F4
998 - F5
999 - Top
By delaying the update and only resuming it next chapter, Oda can time Luffy's arrival for the momentous encounter.
993 - B1
994 - F1
995 - Pause
996 - F2
997 - F3
998 - F4
999 - F5
1000 - Top