I think Address book being a hit at Christmas would have been okay because once Christmas came and went it could have created a clean slate for Quo to return to what the fans want.
In the army now is one of Quo's most popular song even to this day, but it was never a Quo song, but they got away with it somehow. Its currently their most streamed song, when ideally you would think its Caroline or Paper plane or something.
Personally I think Address book being a hit wouldn't have been any worse than Marguerita time, they got away with that too somehow.
But yeah I see your point.
I think looking back over Quos hits, quite a lot of them were bought from non Quo fans, or we're hits due to guilty pleasure type fans, they heard the song on the radio and bought it and hid it quickly behind the single they really went into the shop for.
There was always enough fans who bought the singles to get them into the top 30 or 40,then as the exposure grew, they had major hits on their hands.
Off the top of my head quickly I think What you're proposing, Marguerita time, In the army now, Anniversary waltz, some of Quo's biggest hits became so from people who really would be otherwise a non Quo fan, but because Quo had the knack of coming up with such catchy tunes, people couldn't put them down.
I remember my mate at school or when we were still at school, he said he asked his mother to buy him the single Rock n Roll as he loved it that much, but otherwise can't stand Quo, yet another top ten hit Rock n Roll became, and I am certain it wasn't bought largely by Quo fans.
I think this sort of thing has been going on in most of Quo's career.
I think the only solid true to fans period was probably Dog of two head to Blue for you.
Then Rockin all over the world came out as a single and the face of Quo had changed forever.
Even my parents loved Rockin all over the world, and they only really bought Jim Reeves, or The New Seekers, ABBA, Glen Campbell, that kind of thing, but a few Quo songs rattling out of my bedroom I heard them whistling or humming to afterwards.