LMK app is intended for supportive purposes only related with Post Tensioned (PT) applications and should be used from PT Engineers as a tool to calculate the elongation of a PT tendon.
The user by choosing the basic PT parameters and geometry of the tendon is getting its expected elongation within a reasonable accuracy.
Under no circumstances this app could be used as a structural design software. While every effort has been made to insure its accuracy, should not be used for a specific PT application without professional verification of its suitability and applicability.