So in regards to the conscious sedation time, the intra-service time that they provide in the table is sort of the cut off times before you add another code. Anything less than 10 mins. doesn't qualify to code for conscious sedation but anything 10 mins. or greater will fall into those code ranges. It's not a "hard 15 mins." to meet the requirements to code for it. That's why they provide the table for additional clarification. It's no different than some of the hydration and infusion codes. To code for "each additional hour" of hydration (CPT 96361) you need "intervals of greater than 30 mins. beyond 1 hour increments". If you are able to access CPT Assistants I would recommend reviewing CPT Assistant, June 2017, Volume 27 Issue 6.
With that said the initial conscious sedation service for GI endoscopy services uses the HCPCS code G0500. Any additional time would be captured with 99153 codes, as appropriate.
As far as the second question, what I think you are asking is if we can get greater specificity from the pathology report as far as the location of the polyp. Generally these pathology reports are reviewed by the Gastroenterologist and when the pathology report is available during the time of coding, our facility uses the pathology report with the OP note. So if the provider is giving a description as you state with "X amount of cm from the anal rectal verge" but that sample is marked as the transverse colon and sent to pathology listed as such. We code those to the highest specificity and use the more specific site that the pathologist notes. Every case is different but generally it is acceptable practice in the Outpatient setting to use the pathology report with the OP note if it helps with site specificity. The Gastroenterologist is stating that there is indeed a polyp, so he/she is giving the diagnosis of the polyp. The pathology report is just assisting with site specificity. If that makes sense. If you have access to Coding Clinics I would review AHA Coding Clinic for ICD 2017, First Quarter, Page 15. "Hyperplastic versus Adenomatous Colon Polyps". It sort of helps answer your question as well as additional information on biopsied colon polyps.
If your question was more related to billing/coding for the actual procedure, you just need the appropriate documentation of the technique used to remove the polyp for the colonoscopies. So you shouldn't need the pathology report for coding the procedure itself. Especially since only one technique can be coded regardless of the number of polyps that are removed. I would just cross reference any documentation requirements, NCCI edits and CPT descriptions when necessary.
As a side note, as coders we have to be pretty well versed in human anatomy, as you are aware of I'm sure. So sometimes if I'm unsure where the provider is specifically referencing when he/she is describing so many cm from this point or that point in the colon or really anywhere in the body. I will pull up an anatomy chart. The sigmoid colon is closer to the anal verge than the transverse colon but it's possible that in your OP note the provider is listing how far in the colon he/she is with the scope and they are using the anal verge as a reference point. Just a side note on that.
Hope that helps!