Re-evaluation query

I submitted this answer of mine for re-evaluation, but my marks didnt increase, i still feel that my answer is correct. Could you guys too check and let me know?

second step of 0.5 marks, the marking scheme explanation and my explanation isnt exactly the same but i believe mine is too correct and both lead to the same final result (2EA)

Q Deduce a expression for electric field at a point due to uniformly charged inifnite plane sheet

https://preview.redd.it/y9n6njzwb09h1.png?width=806&format=png&auto=webp&s=1109382c669964ff1fd585d8bb3b7a419620f659

https://preview.redd.it/zxr6snbxb09h1.png?width=781&format=png&auto=webp&s=87d9efd997be9512f02c96176e617959082616ae

https://preview.redd.it/hcxu3xzxb09h1.png?width=799&format=png&auto=webp&s=fea71426f67f00916c10a0738bdad95baed0a459

https://preview.redd.it/unc9sa9yb09h1.png?width=1082&format=png&auto=webp&s=a4aae818d6aa17a3b36d74beba557eaa170878b9