iCloud Backup Sizes ~ Very Confused!!

[Beards]

Guys,
I'm hoping someone can explain the following:-
Until yesterday I was using my iPhone 6 Plus and under Settings/iCloud/Storage/Manage Storage the size of my 6 Plus backup was (and still is) 934.5MB.

I used iTunes and created an 'Encrypted' backup then once all was backed up I then connected my new 6s Plus and did an Encrypted restore (basically copying everything over byte by byte).
Once I had finished this I told iCloud to now wifi backup my new iPhone.

What is weird is both phones settings, menus, all and all are identical ~ yet here's the thing......... Whilst the 6 Plus has a backup size of 934.5MB the 6s Plus has a backup size of 8.3GB!!

I have looked at the backup options data to be backed up and it's identical to the older 6 Plus, even saying "Next Backup Size 85.1MB" but massively different in actual backed up sizes.

It's not the Photo Library as this is backed up separately under iCloud Photo Library.

Any ideas why the two phones differ in such a manner?

 

[Beards]

Any ideas?

 

[adnbek]

Check in the phone's storage usage under settings. I suspect it's from messages or books or other content that you have in one but not the other.

 

[Beards]

Check in the phone's storage usage under settings. I suspect it's from messages or books or other content that you have in one but not the other.

I appreciate you coming back but it's not this. In fact the 6 Plus which has the much much lower backup size has 67.4GB available whereas the 6s Plus with the gigantic backup ha seven more available at 85.6GB.

 

[adnbek]

I appreciate you coming back but it's not this. In fact the 6 Plus which has the much much lower backup size has 67.4GB available whereas the 6s Plus with the gigantic backup ha seven more available at 85.6GB.

Don't look at how much is available. Look at what is using the space here and scroll through. The data being backed up includes things like messages which don't show under the iCloud backup usage details. But something taking a ton of space on your phone is being backed up.

Also plug into iTunes and see how much "other" and "documents and data" are being used in each. I suspect it's that which is causing the discrepancy.

 

[Beards]

Don't look at how much is available. Look at what is using the space here and scroll through. The data being backed up includes things like messages which don't show under the iCloud backup usage details. But something taking a ton of space on your phone is being backed up.

Also plug into iTunes and see how much "other" and "documents and data" are being used in each. I suspect it's that which is causing the discrepancy.

Thanks... I did check the storage including messages etc. Actually messages was higher on the 6 Plus but still only 120MB.
Everything else tallies between both phones.
I'll check iTunes tomorrow thanks.
Another thing I've noticed is although the 6 Plus has carried out another iCloud backup the 6s Plus hasn't bothered to backup automatically despite both phones having identical settings.