solid stain on deck floor

hello

It looks like I have peeling  semi tranapparent stain on my deck floor. my contractor tells me it best to put a solid over top the semi transparent to avoid patches of discoloration He does not believe in trying to strip the old stain off.  Now, everywhere I read your not supposed to put solid stain on floor because it's too thin..

should we use chemical strippers to get old stain off? then brighten and apply semi transparent? or just use a good deck cleaner and apply solid? If a solid what type or can we put over semi tra nsparent?  i read conflicting information related to putting solid on deck floor. can some set the record straight for me at least  attached is pictures of floor