Padded input for ScatteredInterpolant

I am tring to reconstruct a surface in cylinderical coordinate space from set of points. theta,R,z represents azimuthal, radial, axial coordinates, respectively, of measured points. And 0<=theta<360, 0<=z<=200.

Paddedtheta=[theta-360;theta;theta+360];
PaddedR=[R;R;R];
Paddedz=[z;z;z];

RInterpolant=scatteredInterpolant(Paddedtheta,Paddedz,PaddedR,'linear');

However, inquiry RInterpolant at theta=0 and theta=360 does not return identical results:

RInterpolant(repmat(0,[1,201]),0:200)-RInterpolant(repmat(360,[1,201]),0:200)

ans =

   1.0e-14 *

  Columns 1 through 12

         0         0   -0.0888         0         0         0         0         0         0         0         0         0

  Columns 13 through 24

         0         0   -0.0888         0         0         0         0         0         0         0         0         0

  Columns 25 through 36

         0         0         0         0         0         0         0         0    0.0888         0         0         0

  Columns 37 through 48

         0         0         0         0         0         0         0         0         0         0         0         0

  Columns 49 through 60

         0         0         0         0         0    0.0888         0         0         0         0         0         0

  Columns 61 through 72

         0         0         0         0         0         0         0         0         0         0         0         0

  Columns 73 through 84

         0         0         0         0         0         0         0         0         0         0   -0.0888         0

  Columns 85 through 96

         0         0         0         0    0.0888         0         0         0         0         0         0         0

  Columns 97 through 108

         0         0         0         0         0         0         0         0         0         0         0         0

  Columns 109 through 120

         0         0    0.0888         0         0         0         0         0         0         0   -0.0888         0

  Columns 121 through 132

         0         0         0         0         0         0         0         0         0         0         0         0

  Columns 133 through 144

         0         0         0         0         0         0         0         0         0         0         0         0

  Columns 145 through 156

         0         0         0         0         0         0         0         0         0         0         0         0

  Columns 157 through 168

         0         0         0    0.1776         0         0         0         0   -0.0888         0         0         0

  Columns 169 through 180

         0         0         0         0         0         0         0         0         0         0         0         0

  Columns 181 through 192

         0         0         0         0         0         0         0         0         0         0         0         0

  Columns 193 through 201

         0         0         0         0         0         0         0         0         0

Could anyone tell me why?

[darova]

THe error is very small

ans =
   1.0e-14 *
  Columns 1 through 12

[Yi-xiao Liu]

I understand the error is small. I am just curious the cause as I was not expecting any