Boundary/Trisurf not properly defining curvature in surface plot

I'm currently working on a project that includes defining the following surface:

Here you can see a large set of scatter data (red and green) combined into a single set of data that ive used in the following code to define a surface:

Composite = sortrows([LDPhase;LOPhase],3);

X = (Composite{:,1}*pixel);
Y = (Composite{:,2}*pixel);
Z = (Composite{:,3}*pixelY);

hold off
scatter3(LOX,LOY,LOZ,'.', 'g','MarkerFaceAlpha', .3, 'MarkerEdgeAlpha', .1)
hold on
scatter3(LDX,LDY,LDZ,'.', 'r', 'MarkerFaceAlpha', .3, 'MarkerEdgeAlpha', .1)
hold on
axis equal

P = [X,Y,Z];
k = boundary(P,.68);

trisurf(k,P(:,1),P(:,2),P(:,3),'Facecolor','green','FaceAlpha',0.1,'EdgeAlpha',.5)
[~,vol] = boundary(P,.55);

My problem is: the surface described by boundary/trisurf do not include some of the important curvature of my data, regardless of what shrink factor i use.

seen here:

Is there some way I can effectively include this curvature? I would greatly prefer to keep the boundary function, as much of the code i've wirtten following this relies on the output 'k'.

Thank you for any help,

Chris