Different result from sptransform() and ptransform()

Hi!
I'm reprojecting and get different results from sptransform() than
from ptransform():
(objec cents in https://sites.google.com/site/filestemp2/home/cents.rda)

str(cents,max.level=2)

Formal class 'SpatialPointsDataFrame' [package "sp"] with 5 slots
  ..@ data       :'data.frame':	234 obs. of  4 variables:
  ..@ coords.nrs : num(0)
  ..@ coords     : num [1:234, 1:2] 3603500 3604500 3605500 3606500 3607500 ...
  .. ..- attr(*, "dimnames")=List of 2
  ..@ bbox       : num [1:2, 1:2] 3603500 2155500 3620500 2167500
  .. ..- attr(*, "dimnames")=List of 2
  ..@ proj4string:Formal class 'CRS' [package "sp"] with 1 slots

proj4string(cents)

[1] " +init=epsg:3035 +proj=laea +lat_0=52 +lon_0=10 +x_0=4321000
+y_0=3210000 +ellps=GRS80 +units=m +no_defs"

centslonlat <- spTransform(cents,CRS("+init=epsg:4326"))
coordinates(centslonlat)[1:3,]

X        Y
[1,] 1.315311 42.23956
[2,] 1.327326 42.24060
[3,] 1.339342 42.24163

a <- ptransform(data = as.data.frame(coordinates(grid1km)), src.proj = CRSargs(CRS("+init=epsg:3035")), dst.proj = CRSargs(CRS("+init=epsg:4326")))
coordinates(a)[1:3,]

x         y z
[1,] 0.02295650 0.7372194 0
[2,] 0.02316621 0.7372375 0
[3,] 0.02337593 0.7372556 0

The correct results are those from sptransform(), but I would like to
know what I'm doing wrong with ptansform()

Thanks

Agus