In September 2017 we purchased 12 x Deka Marine Master flooded G31 batteries. If you are still in the Annapolis MD area, I strongly reccommend that you buy them from Stevens Battery Warehouse in Annapolis. (https://www.stevensbattery.com)
We paid US$120 for each battery and with sales tax the total came to US$1624 for all 12 batteries. The staff is super friendly and they will load test each new battery right in front of you so you know it's good. They have them in stock by the pallet and seem to turn their inventory over quickly as the batteries we purchased in September had stickers saying they were manufactured in July 2017. They also carry the Deka AGM Intimadator batteries as well as Lifeline brand batteries.
Deale, MD USA