Not so sure about that one...
I concur
I frequently dive to 30M on a wreck over here on the east coast of UAE with EAN32, so I ran the numbers on Multideco to dive it with no deco gases and only using a 20/40 mix which is what I usually use for my deeper dives, and with air, see below;
DIVE PLAN
Surface interval = 1 day 0 hr 0 min.
Elevation = 0m
Conservatism = GF 15/75
Dec to 30m (3) Trimix 20/40 10m/min descent.
Level 30m 27:00 (30) Trimix 20/40 0.80 ppO2, 10m ead, 14m end
Asc to 18m (32) Trimix 20/40 -6m/min ascent.
Stop at 18m 1:00 (33) Trimix 20/40 0.56 ppO2, 4m ead, 7m end
Stop at 15m 1:00 (34) Trimix 20/40 0.50 ppO2, 3m ead, 5m end
Stop at 12m 2:00 (36) Trimix 20/40 0.44 ppO2, 1m ead, 3m end
Stop at 9m 4:00 (40) Trimix 20/40 0.38 ppO2, 0m ead, 1m end
Stop at 6m 2:00 (42) Trimix 20/40 0.32 ppO2, 0m ead, 0m end
Stop at 5m 39:00 (81) Trimix 20/40 0.30 ppO2, 0m ead, 0m end
Surface (86) Trimix 20/40 -1m/min ascent.
OTU's this dive: 20
CNS Total: 6.7%
DIVE PLAN
Surface interval = 1 day 0 hr 0 min.
Elevation = 0m
Conservatism = GF 15/75
Dec to 30m (3) Air 10m/min descent.
Level 30m 27:00 (30) Air 0.84 ppO2, 30m ead
Asc to 18m (32) Air -6m/min ascent.
Stop at 18m 1:00 (33) Air 0.59 ppO2, 18m ead
Stop at 15m 1:00 (34) Air 0.52 ppO2, 15m ead
Stop at 12m 1:00 (35) Air 0.46 ppO2, 12m ead
Stop at 9m 3:00 (38) Air 0.40 ppO2, 9m ead
Stop at 6m 1:00 (39) Air 0.34 ppO2, 6m ead
Stop at 5m 24:00 (63) Air 0.31 ppO2, 5m ead
Surface (68) Air -1m/min ascent.
OTU's this dive: 22
CNS Total: 7.6%
So, 86 mins using He and 68 mins using Air
Mmmm so does having an additional 1% O2 make much difference
DIVE PLAN
Surface interval = 1 day 0 hr 0 min.
Elevation = 0m
Conservatism = GF 15/75
Dec to 30m (3) Triox 21/40 10m/min descent.
Level 30m 27:00 (30) Triox 21/40 0.84 ppO2, 10m ead, 14m end
Asc to 18m (32) Triox 21/40 -6m/min ascent.
Stop at 18m 1:00 (33) Triox 21/40 0.59 ppO2, 4m ead, 7m end
Stop at 15m 1:00 (34) Triox 21/40 0.52 ppO2, 2m ead, 5m end
Stop at 12m 1:00 (35) Triox 21/40 0.46 ppO2, 1m ead, 3m end
Stop at 9m 4:00 (39) Triox 21/40 0.40 ppO2, 0m ead, 1m end
Stop at 6m 2:00 (41) Triox 21/40 0.34 ppO2, 0m ead, 0m end
Stop at 5m 36:00 (77) Triox 21/40 0.31 ppO2, 0m ead, 0m end
Surface (82) Triox 21/40 -1m/min ascent.
OTU's this dive: 22
CNS Total: 7.6%
Not really, only 4 mins less deco, unless I have screwed up somewhere