Interac ALT here. Is it worth applying to JET or Altia?

I'm on my second year as an ALT in Interac. Love the country, love my placement, but money's tight. I'm working on certifications and improving my Japanese for a career change, but that's a little ways out. I'm planning on teaching for one more school year after this one, and I hear Altia and Jet pay the best out of all the ALT options.

Is it worth applying to them for the extra pay? Even an extra couple thousand yen a month would give me some breathing room. Would switching dispatch companies look bad or would they just be happy to see an applicant that already lives in Japan?