Yeah I think the merging methods are acting up depending on the shape of the ships.

Can you send a blueprint of the ship ? But place the tank where you wanted it to be and paint it something ridiculously obvious like bright purple, I'll do some experiments and try to make that work.

It finally worked though I had to remove the back two wall blocks, I'll see if I can replicate the bug either this evening or tomorrow. I'm also uploading a pic of my second attempt that failed.

2nd attempt: http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=574757703
the pads were attached at the bottom to the cargo container and a space was left in between.

http://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=575360356

Well I found the cause, which is if the smaller grid has its pivot too far away from the weld pad then any small rotation will result in a final-merge offset.

That's why in my tests it didn't have this issue because I mostly tested with few blocks and mostly created new ships which had the pivot close to the weld pad.

I'll need to do some more calculations in order to avoid that... it might take a while xD

alright, can't wait.

Right, I think it should be fine now, I've tested with your station in a bunch of angles with new ships and with parts separated from the station relocated as well.

Alright, thanks