Doesn't seem that way and does not seem to match what ddowiki says:
https://ddowiki.com/page/Experience_point#XP_example
Voice, Ship Buffs, VIP, and XP Elixirs are applied to "subtotal", all the normal bonuses are applied to "base".
It is exactly how Shear says. The VIP bonus is (normally) 10% which is additive with ship/voice/pots and that total is multiplied on the "subtotal" quest xp (which is kind of the xp you see in the quest window, except when the daily-run bonus is display-bugged and not showing). Those 10% is close to a 10% real bonus, since even with ship/voice and a 20% pot for instance, you'll go from a 40% bonus to a 50% with VIP (in this case, a 1/14th increase in XP awarded, or 7ish %)
The 1% per member, on the other hand, is added to the bucket where delving, ransack, conquest, traps, doors, no-deaths, no-reentry, tome of learning etc. Let's look at case B on the wiki:
First reaper 45%
Delving 150%
Conquest 25%
Ransack 15%
Flawless 10%
Persistence 10%
Greater tome 50%
Daily 25%
This is a total of 330%. The group bonus is actually mentioned under Case A, btw, in the section with these bonuses.
If a VIP has a full group, he'll get another 5% on top of that 330% bonus. So total (including base xp) would go from 430% (330+base 100) to 435%, an increase of 1.16%. Which is very meh.
I agree that the wiki could be a little confusing on this point, since it doesn't spell out too clearly that the 1% is on another channel than the regular VIP bonus. But it does actually say "small group bonus" to xp, and in Case A the group bonus is indeed added in this channel with delving and so on.