Have an old seasonal camp in Northern Maine. Probably painted 30- or 40 years ago with a flat white oil-base paint. Some chalking and peeling now - but not too bad. Want to repaint with acrylic latex. Brought in 6 pro painters for estimates. Each one proposed to scrape, spot prime and put on a coat of good latex paint (my choice). None mentioned putting on a coat of oil-based primer to make the transition to latex. When I suggested it - was told it wasn't necessary. When I asked the paint manufacturer - was told it was recommended. Any comments or suggestions??