OB1203 certification process

My name is Nikola Stankovic and I am R&D engineer at ES Design Center company. We have used yours OB1203 SpO2 sensor in our device for
measuring patient's SpO2 level. Now we are in obligation to do certification of this device of ours. I have found at your web site document
"OB1203 Certification Preparation, Setup, and Test Procedure", which is my main guide in this certification process. In order to understand
this certification process I tried to replicate and follow this document. Unfortunately there are some steps which I can't quite understand
and can't replicate, which at the end make's my job really hard. So, in order to overcome these problems I am asking you for help and clarification
of certain steps described in this document of yours.

We have obtain WhaleTeq AECG100 testing equipment and produce conical shape testing jig as it is described in your document. In our device
(Device Under Test - DUT) we have used your algorithm for SpO2 measurement, which is provided in your web site. We do have your OB1203SD-RL-EVK
development kit, but without LCD screen. For results presentation this development kit board uses USB connection to PC and any terminal program
in PC (TeraTerm, Hyper, Putty etc.). Since we are using (in DUT) the same algorithm for SpO2 calculation as your evaluation board OB1203SD-RL-EVK,
we are getting pretty much the same results for first step (described at Chapter 5 of "OB1203 Certification Preparation, Setup, and Test Procedure" document).
The problems are starting at next step (described at Chapter 6). Since we (in our DUT) have additional glass window between OB1203 sensor and patient's finger,
I tried to find out what is correction of SpO2 readings induced by external optical crosstalk (introduced by additional glass window). When I followed instructions from
this document (Chapter 6), by covering my glass window with black tape, I am not getting any readings from OB1203 sensor. Then I have noticed that your window
have some black tape cover at its middle part and openings at both sides, which is not in my case (window). Can you provide me any hint how to calculate this
optical crosstalk in my case. My window is very simple. Just oval shape, aprox. 9mm in diameter, 1mm thickness, acryl plastic. No additional features, like central part cover.

Second problem that I have encountered is at Chapter 7, which determines dark skin sensitivity. I have tried to follow the instructions from document, step by step,
but one thing is not clear to me. I have adjusted everything in PC application as described and at step 5. I tried to variate IR AC values, but changing this parameter
I am also changing SpO2 in PC application, which is previously set at 90%. So, do I have to ignore SpO2 from PC application and try to get DUT SpO2 readings within
of 86.5 to 93.5%. Because, in order to get DUT SpO2 readings within this range ( 86.5 to 93.5%) I have to vary A LOT IR AC value, and then SpO2 PC application readings are
way off 90%.