glued laminated appearance grades

huangyhg

glued laminated appearance grades
the project is a church.  ninety percent of the glulam members are exposed.  ten percent of the glulam members are concealed above a dropped ceiling, soffit or elsewhere.  
i am aware of (4) appearance grades:  industrial, industrial s, architectural and premium.  (what is "industrial s"?)
i am specifying the appearance grade to be "architectural".  is there a cost benefit in specifying the concealed ten percent as industrial, or is the cost savings little to nothing?
thank you!
see link for standard appearance grades for structural glued laminated timber, aitc-110 at:
to the best of my knowledge industrial s, is not a standard aitc grade.  when speaking of industrial grade glulams, some times the terms "as is" and "clean" are used with industrial.
industrial "as is", is the condition it comes out of the glue form.  it will have glue squeeze out, may have dirt on the beams.  with industrial "clean" generally the beams will be cleaned up generally by rough sanding or by running them through a planer.  as a general rule voids will not be filled.
there is an official industrial appearance grade, which has specific requirements regarding; the filling of knot holes on the wide face of laminations exposed to view and specific finishing requirements.  this information is given in      aitc 110.
at one time industrial appearance was used as exposed members in some structures to reduce costs.  for example in the past it was fairly common for churches to use industrial appearance grade.
now it would be rare to see industrial appearance specified for exposed applications.  these days, i think industrial is used as a description for beams which are not exposed or are used in applications where appearance is not a concern.
what i would do is specify that all exposed glulams be architectural grade.  there would be quiet a bit of a savings for using indstrial grade on the non exposed beams.  i have probably done shop drawings where out of forty or fifty beams, only two were not exposed.  i still called out the two beams as industrial.