I'd found that a lot of people weren't aware that there's a grenade throwing arc available as the second perk, and I can't blame them with the way the progressive ranks in perks are "hidden". This mod makes the grenade throwing arc accessible from the FIRST rank of Demolitions Expert (only requirement is PERCEPTION @ 5). 

Also available is a standalone perk that JUST adds the grenade throwing arc. You can access it via the console:

help "grenade arc" 4

Use the results to replace 'XX'

player.addperk XX000800