i have an ask? (help)

Apologies. My mistake. Try this code instead:

let
  Source = Table.FromRows(
    Json.Document(
      Binary.Decompress(
        Binary.FromText(
          "NY25DcAwDAN3cc1CjyVLsxjef40EodMdyAO599AUWI2DPaYj9COVgDdRCx3EoNcJIa3rmECMWAKnHvPfaGG3GnmnFpVGOQNP2D0vvNJ5AA==",
          BinaryEncoding.Base64
        ),
        Compression.Deflate
      )
    ),
    let
      _t = ((type nullable text) meta [Serialized.Text = true])
    in
      type table [Gepland = _t]
  ),
  #"Changed Type" = Table.TransformColumnTypes(Source, {{"Gepland", type number}}),
  #"Duplicated Column" = Table.DuplicateColumn(#"Changed Type", "Gepland", "Gepland - Copy"),
  #"Multiplied Column" = Table.TransformColumns(
    #"Duplicated Column",
    {{"Gepland - Copy", each _ * 100, type number}}
  ),
  #"Extracted Last Characters" = Table.TransformColumns(
    #"Multiplied Column",
    {{"Gepland - Copy", each Text.End(Text.From(_, "es-ES"), 2), type text}}
  ),
  #"Changed Type1" = Table.TransformColumnTypes(
    #"Extracted Last Characters",
    {{"Gepland - Copy", Int64.Type}}
  ),
  #"Divided Column" = Table.TransformColumns(
    #"Changed Type1",
    {{"Gepland - Copy", each _ / 100, type number}}
  ),
  #"Multiplied Column1" = Table.TransformColumns(
    #"Divided Column",
    {{"Gepland - Copy", each _ * 60, type number}}
  ),
  #"Rounded Off" = Table.TransformColumns(
    #"Multiplied Column1",
    {{"Gepland - Copy", each Number.Round(_, 0), type number}}
  ),
  #"Changed Type2" = Table.TransformColumnTypes(#"Rounded Off", {{"Gepland - Copy", type text}}),
  #"Added Conditional Column" = Table.AddColumn(
    #"Changed Type2",
    "Custom",
    each if [#"Gepland - Copy"] = "0" then "00" else [#"Gepland - Copy"]
  ),
  #"Inserted Merged Column" = Table.AddColumn(
    #"Added Conditional Column",
    "Merged",
    each Text.Combine({"0", [#"Gepland - Copy"]}),
    type text
  ),
  #"Changed Type3" = Table.TransformColumnTypes(
    #"Inserted Merged Column",
    {{"Gepland - Copy", Int64.Type}}
  ),
  #"Added Conditional Column1" = Table.AddColumn(
    #"Changed Type3",
    "Custom.1",
    each if [#"Gepland - Copy"] < 10 then [Merged] else [Custom]
  ),
  #"Inserted Text Before Delimiter" = Table.AddColumn(
    #"Added Conditional Column1",
    "Text Before Delimiter",
    each Text.BeforeDelimiter(Text.From([Gepland], "es-ES"), ","),
    type text
  ),
  #"Inserted Merged Column1" = Table.AddColumn(
    #"Inserted Text Before Delimiter",
    "Final",
    each Text.Combine({[Text Before Delimiter], ":", [Custom.1]}),
    type text
  ),
  #"Removed Columns" = Table.RemoveColumns(
    #"Inserted Merged Column1",
    {"Gepland - Copy", "Custom", "Merged", "Custom.1", "Text Before Delimiter"}
  )
in
  #"Removed Columns"

Something I din't mention is that the minutes are rounded to the nearest minute!