It is normal to have a gap of that size when the surface is fully deflected down- but- it looks like your builder cut back the top front wing skin 3/16 or so. He probably did this to keep from having catching when the sufrace is deflected up. The flight surface skin should slide under the wing skin when deflected perhaps he didnt know this. I dont know if it will be a problem-gonna catch a lot of air, especially when deflected down. Scott