What type of exposure set-up do you have? It is possible that your light source is not casting a true shadow of the film onto the screen and is shifting a bit. You should try to register the positive to the screen after you wash out to see how accurate it is burning.
Do you notice as the sun moves across the sky, the shadows of poles move? But the pole do not move, it remains stationary. The light source is just shining on it at a different angle.
So when you line up the screens on press, the actual burn will perfect on some areas but not perfect in other areas. This can happen alot with box exposure units with multiple lights sources as well as single light source that is too close to the screen during the burn.
For a larger design you may have to to move your light source further away and burn longer.
You need to make sure that the film is burning into the screen straight and true so the image washes out exactly like the film.
I have experienced the same thing at times. I don't have an ink-jet (wish I did). What I have found even using a laser jet is I can run edge to edge if I follow a proceedure I have learned. We don't need to get into that here.
Meantime 1pt. is good. I run an auto and what I do is line up the top and lock it in and fudge the bottom over till it lines up and lock it in.
Lately I have slowly, due to cash been replacing all of my wood screens with static aluminum Sefar frames.
Today I set up a four color on polyester tech shirts. EVERYTHING is backed in white due to poly sublimation issues. I have 4pt text and grapichs surrounded by 1 to 3 pt borders. Lines up perfect and the detail even with reversed text holds.
Not sure what I am trying to get across here except I wish I had an ink jet and more of these frames. I print everything with 230's. 110's are...
Yes you must have a single point light source.
Hmm, What else? Level platens, squeegy and flood bar, with just the right amout of pressure on both.
Humidity is a problem.
Screen Printing is rocket science/finesse and there are no magic buttons.
Get good frames/mesh and line up your screens to your art, not a print of one of the colors.
Tri-lock is next.