Firstly - always go by what Data Robotics say as best practice.
Having said that the new 4k Advanced Format Drives appear to any computer or storage device as a typical hard drive. Even though things are stored in 4K sectors internally, the disk still presents itself as a series of 512byte sectors - like any typical hard disk.
The problem with these drives is when the operating system formats the disk into clusters (say 4K for NTFS) and these do not properly align with the 4K size sectors used on the physical disk. The result is that whenever you write anything out to a 4K cluster on your filesystem it is spread across two 4K sectors on the physical disk.
So every one write at the OS level generates two writes at the disk level (actually since the sectors need to be read into cache to be partially updated it also results in a couple of disk reads). The disks work - they just perform really poorly.
The only danger you may get with Drobo is the disks being too slow and possibly being kicked out as bad - i’m not sure on how likely that is.
In regards to the jumper on the Hard Disk - this is a specific fix for Windows XP and earlier Operating Systems. Under Windows XP NTFS is misaligned by one 512k sector. The jumper offsets everything by 1 so that when the OS asks for sector 63 it actually gets 64 on the physical disk - so it aligns properly.
Unless Drobo happened to misalign its partitions in exactly the same way the jumper won’t make any difference.