'data' folder and permission - Clarification Request

In previous Elgg releases, the 'data' folder, (outside of document root). had permissions requirement as '770' according to the Official Elgg Installation Document; however, with recent releases, the the permission requirement for the said folder has changed from 770 to '750'.

When I first started with Elgg 1.2x branch, I had to obtain paid SSH service to crate the data folder outside /www/ in a Debian VPS Hosting Service. At that time, I created the data folder under '/data' with permission as '770', and the full path of the data directory appeared as '/home/data/'. Since, then I no longer subscribe to the paid SSH.

With new releases, I have sorted the data folder a bit differently. For example /data/dataroot/ which on Elgg Admin side appears as  '/home/data/dataroot' as full path of the data directory.

My question is, now that the revised Elgg Installation document calls for 'data' folder permission to be '750'; but mine remains as '770'; is it really necessary to change it to 750? For your information, I have following sub directories under parent  /data   directory:    
                                                                                                                                                                    /dataroot (770) ( /data/ dataroot)
                                                                                                                                                                   /cacheroot (770) (/data/ cacheroot)
                                                                                                                                                                  / ckeditor (770) (/data/ckeditor)
and files residing under above subdirectories are set as '644'.

It's working for me.............. but I am confused because '770' basically means that data directory is owned by the web server, but not true when permissions are set as '750'. Nevertheless, with the exception of 'data' folder, which is already set to 770 several years back, I can change permissions of all the sub directories - 'dataroot', 'cacheroot', and 'ckeditor' as 755; but I see 770 as elevated and secured permission over or '750' in my case.

As said earlier, it's working for me, but the new '750' requirement is always on my mind. I humbly ask any members of the Elgg Community, to clarify if I should:

1. keep /data/<sub directories> as 770 for parent (data) and 770 child (sub directory) directories as well and permission '644' for any files residing under the directories such as  'scraper_cache.dat' or  'queue.db' and all ckeditor asset files for embedding.  

2, 770 for parent (data) and 750 for child directories and let the files be as 644.

3. Once again subscribe to paid SSH service and change the data folder permission as '750' as per new guideline?

I look forward to an answer. Thanking you in anticipation.