@Diego Draper, It should work on your G350/G370s(as I have it working at the CoE on G370's as well)
See the note here:
https://knowledge.hitachivantara.com/Documents/Management_Software/SVOS/9.5/Global-Active_Device/10_Maintenance_of_global-active_device#Expansion_of_DP-VOL_capacity_while_keeping.0D.0A____pair_status
You can expand the capacity of a DP-VOL used in the GAD, TrueCopy, Universal Replicator, ShadowImage, or Thin Image pair created between or on the following storage systems while keeping the pair status in each software product.
- VSP 5000 series: Microcode version 90-04-04-00/00 or later
- VSP G/F350, G/F370, G/F700, G/F900: Microcode version 88-06-02-x0/00 or later
- VSP E990: Microcode version 93-02-03-x0/00 or later
Note: The expansion of DP-VOL capacity on the storage systems shown cannot be used with the expansion of DP-VOL capacity, which was supported for VSP G1x00, VSP F1500 with microcode version 80-06-74-xx/xx or later, while keeping a GAD pair status.