Converting mouse position way off - c++

Question

I've got a remote screen that takes mouse position then converts the position into the captured screens position but the position is always off. I'm not the greatest at math but I'm sure my conversion is correct. The image size I get in correlation with the screen along with the window size is correct. The only thing that ends up being off is my click point after conversion.
** Also I know I have no error checking. This is to help with readability.
EXAMPLE: I want to click on Screen point 1102x 999y. The Remote Window point is approx 676 584. After conversion the point gets translated to 1081.5 935.3. I would understand maybe a few pixels off because its hard to click on that exact spot through the RW but its getting translated 60 pixels up and 20 pixels left.
Lets say that my remote screen is 800 x 600 and the captured is 1280 by 1024.
to get the difference I use (1280 / 800)*Clickpointx and (1024 / 600)*Clickpointy.
My problem is sWidth and sHeight are always off by at least 20 and sometimes are off by upwards of 80 depending on where the click is inside the window.
POINT p;
float sWidth;
float sHeight;
GetCursorPos(&p);
RECT rect;
GetWindowRect(hWnd, &rect); // Get Window Size
ScreenToClient(hWnd, &p); // convert points relative to screen to points relative to window
float wWidth = rect.right - rect.left;
float wHeight = rect.bottom - rect.top;
Gdiplus::Image* image = Gdiplus::Image::FromStream(sRemote_Handler.istream); //Get Captured image Size;
float iWidth = image->GetWidth();
float iHeight = image->GetHeight();
INPUT input;
input.type = INPUT_MOUSE;
input.mi.time = 0;
float pointx = p.x;
float pointy = p.y;
sWidth = (iWidth / wWidth)*pointx; // divide image width by screen width
sHeight = (iHeight / wHeight)*pointy; // divide image height by screen height
input.mi.dx = sWidth*(65536.0f / iWidth); //convert to pixels
input.mi.dy = sHeight*(65536.0f / iHeight); // ^
input.mi.dwFlags = MOUSEEVENTF_ABSOLUTE | MOUSEEVENTF_MOVE;
SendInput(1, &input, sizeof(input)); // move mouse
I've tried changing the conversion method to (Clickpointx*1280)/800 and (Clickpointy*1240)/600. Still the same results.
sWidth = (pointx * iWidth) / wWidth;
sHeight = (pointy * iHeight) / wHeight;
Changed the conversion method once more. Same Results
sWidth = (pointx / iWidth)*wWidth;
sHeight = (pointy / iHeight)*wHeight;
EDIT
I've came to the conclusion that its the ScreenToClient windows function.
When clicking in the bottom right corner which should be damn near 800,600 both values are around 50 less then what they should be. When I click in the top left both values are where they should be. The numbers are reporting as 0,1. It seems as though the further I get from the initial 0,0 point the less accurate ScreenToClient gets.