Ridge vents vs turtle vents or both

I am replacing a shingle roof (47 sq) after hail damage. The roof is on a two story house, attached 3 car garage, and has a highly complex, steep pitch design. There are ridge vents in every location that they will fit with soffit vents around the entire structure. Two zoned AC units and two 40 gallon water heaters are in the attic space. There are also several turtle vents in the roof, mainly over the “hot” spots - furnaces and hot water heaters. My contractor wants to cover over all the turtle vents and just replace the ridge vents. He says that makes the ridge vents more effective. Our subdivision is only 4 years old with all high end houses and every one has both ridge and turtle vents. Is my contractor right and all the builders wrong in the design of their roofs? I am leaning towards making him replace the turtle vents but would like more expert advice before forcing the issue. Thanks.

Ok he is correct about mixing the vents. On a home with all the heaters and water heaters in the attic it is advisable to remove the ridge vent and go with straight turtle vents. They can be over the hot spots along with the rest of the roof. Ridge vent will be disrupted if the turtle vents are there.