So, tonight was my first time doing a BIAB batch with my new equipment. I have an 11 gallong Bayou Classic kettle with the SS basket which I put my bag in. I was doing an IPA recipe w/ 13 pounds of grain. I heated 7.5 gallons to 161 degrees and added in the grains and the temp dropped to 153 (target mash temp of 152). I constantly stirred the grain while pouring in with a 24" whisk. Mashed at 152-3 for 60 minutes, after 60 minutes temp was at 150. The preboil hydrometer meeting came out to 1.27 @ 151 degrees and 7.0 gallons, resulting in around 62% efficiency (1.042 adjusted, but target was like 1.058?). What did I do wrong? I ended up tossing in 1lb of DME during the boil to bring up my final OG to 1.061 (target 1.067), but still, how can I get my BIAB system to be up around 70-80% like most claims i read about?