I am trying to plot the effect on Value of an interaction between Trend and Experience, at high vs. low levels of Trend.
(I would like to see the effect of value of Experience in high vs. low trend levels)

First, I ran the regression of value on Trend, Experience, Interaction, and my controls,

Second, I used the following code:
margins, at(Trend=(2.09 4.53) Experience =(0 .75 1.5 2.25))
In the Parentheses, I added for Trend the average +/- standard-deviation; and for Experience few observations to generate scenarios for the graph.

To obtain the Graph, I then added the following code:
marginsplot, xdimension(Experience) recastci(rarea)

This resulted in two lines that are perfectly parallel with their areas that are perfectly similar. I have repeated this exercise using Excel and the results are not the same. Specifically, the slope of the two lines (at 2.09 and 4.53) are not the same.

Can anyone advise what could be the problem in the code? Thanks.